scholarly journals Sulphate Resistance of Boron Active Belite Cement Concrete

2020 ◽  
Vol 1 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Abdulkadir Cüneyt AYDIN
Keyword(s):  
Compressive Strength ◽  
Ultrasonic Velocity ◽  
The Other ◽  
Weight Increase ◽  
Chemical Effect ◽  
Unit Weight ◽  
Control Group ◽  
Cement Concrete ◽  
Ultrasound Measurements ◽  
Belite Cement

The sulphate resistance of variable concretes, including Boron active belite cement (BABC), CEM I 42.5 R and CEM II 32.5 B-S cements, were determined in the present study. The compressive strength, ultrasonic velocity, Schmidt, and unit weight tests were applied to steam cured and water cured samples. Three Na2SO4 solutions of %5, %10 and %20 were prepared for each type of concrete except for the control group and the samples were exposed to the effect of sulphate solutions for 24 weeks. As a result, weight increase was determined in CEM I 42.5 R cement samples the least, and in BAB cement samples the most. As expected, pronounced chemical effect was not observed in samples of cement CEM II.32.5 B-S. On the other hand, while decreases or slight increases were observed in the ultrasound measurements of CEM I 42.5 R cement samples after sulphate test, critical increases were observed in BAB and CEM II 32.5 B-S cement samples. Under sulphate effect, water and steam cures had explicit effects on pressure resistances.

scholarly journals A Study on the Thermal Properties of High-Strength Concrete Containing CBA Fine Aggregates

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1493 ◽  
Author(s):  
In-Hwan Yang ◽  
Jihun Park
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Ultrasonic Velocity ◽  
High Strength Concrete ◽  
High Strength ◽  
Unit Weight ◽  
Test Results ◽  
Strength Concrete ◽  
Fine Aggregates

The thermal conductivity of concrete is a key factor for efficient energy consumption in concrete buildings because thermal conductivity plays a significant role in heat transfer through concrete walls. This study investigated the effects of replacing fine aggregates with coal bottom ash (CBA) and the influence of curing age on the thermal properties of high-strength concrete with a compressive strength exceeding 60 MPa. The different CBA aggregate contents included 25%, 50%, 75%, and 100%, and different curing ages included 28 and 56 days. For concrete containing CBA fine aggregate, the thermal and mechanical properties, including the unit weight, thermal conductivity, compressive strength, and ultrasonic velocity, were measured. The experimental results reveal that the unit weight and thermal conductivity of the CBA concrete were highly dependent on the CBA content. The unit weight, thermal conductivity, and compressive strength of the concrete decreased as the CBA content increased. Relationships between the thermal conductivity and the unit weight, thermal conductivity and compressive strength of the CBA concrete were proposed in the form of exponential functions. The equations proposed in this study provided predictions that were in good agreement with the test results. In addition, the test results show that there was an approximately linear relationship between the thermal conductivity and ultrasonic velocity of the CBA concrete.

MELATONIN ON ENDOCRINE DNA CHANGES IN FEMALE RATS AT INCREASING AGES

1971 ◽  
Vol 68 (3) ◽  
pp. 597-604 ◽  
Author(s):  
D. V. Singh ◽  
C. W. Turner
Keyword(s):  
Body Weight ◽  
Treated Group ◽  
The Other ◽  
Female Rats ◽  
Unit Weight ◽  
Control Group ◽  
Uterine Weight ◽  
Endocrine Glands ◽  
Sprague Dawley ◽  
Total Dna

ABSTRACT Sixty female Sprague-Dawley-Rolfsmeyer rats were divided equally into three groups, twenty in each group at 25 days of age. One half of each group serving as controls received saline, the other half received 100 ftg melatonin/100 g body weight at 25, 35. and 45 days of age, for 10 days. They were killed 24 hours after the last injection. Pituitaries. ovaries, uteri, adrenals and thyroids were collected and weighed. DNA determination by the method described by Webb Se Levy (1955) was used for ovaries, uteri and adrenals only. Pituitary weight was not affected much by the treatment of melatonin. Thyroid weight increased: adrenals, ovaries and uterine weight decreased gradually up to 55 days in melatonin treated group as compared to the control. Ovarian total DNA increased significantly at 35 days of age, but significantly decreased at 45 and 55 days of age in melatonin treated group as compared to the corresponding controls. No difference in total DNA in adrenals was found in melatonin treated animals as compared to control group at any age. The total DNA of the uteri increased 29 % at 35 days of age but decreased at 55 days of age by 14%. These data also show that the DNA/mg of endocrine glands dry fat free tissue decreased with increasing age suggesting a reduction in functional cells per unit weight in older animals.

scholarly journals A Comparative Study on the Thermal Conductivity of Concrete with Coal Bottom Ash under Different Drying Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
In-Hwan Yang ◽  
Jihun Park ◽  
Kyoung-Chul Kim ◽  
Sung-Won Yoo
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Fly Ash ◽  
Ultrasonic Velocity ◽  
Bottom Ash ◽  
Unit Weight ◽  
Coal Bottom Ash ◽  
Concrete Mixtures ◽  
Drying Conditions

The utilization of coal bottom ash (CBA) and fly ash in concrete has become more common. For CBA concrete, curing conditions would influence the thermal properties of the concrete due to the high water absorption capacity of the CBA aggregate. In addition, CBA and fly ash contents in concrete affect the thermal properties of the concrete. Therefore, the effects of the drying conditions and the CBA and fly ash contents on the thermal conductivity of CBA concrete were investigated in this study. The thermal conductivity of concrete was measured under two different curing and drying conditions: oven-dried conditions and saturated surface-dry (SSD) conditions, with curing times of 28 and 91 days. The concrete mixtures also contained different levels of CBA and fly ash. Crushed sand in the concrete mixtures was replaced by CBA with replacement ratios of 25%, 50%, 75%, and 100% by volume. In addition, cement in the concrete mixture was substituted by fly ash with replacement ratios of 20 and 40% by volume. The thermal conductivity of concrete under the oven-dried conditions was much lower than that under the SSD conditions. Moreover, the thermal conductivity of the concrete decreased as the CBA content increased under both the oven-dried and SSD conditions. The material properties of the concrete, including unit weight, compressive strength, and ultrasonic velocity, were also measured in the study. Compared with the SSD conditions, the compressive strength, unit weight, and ultrasonic velocity of CBA concrete were considerably lower under the oven-dried conditions. Moreover, the relationships between the thermal conductivity and unit weight, compressive strength, and ultrasonic velocity were suggested.

scholarly journals Investigation of the Effect of Freeze-thaw Cycles on the Mechanical Properties of Hardened Self-compacting Concrete

2020 ◽  
Author(s):  
Tuncay Kap
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Statistical Analysis ◽  
Fresh Concrete ◽  
The Other ◽  
Unit Weight ◽  
Self Compacting Concrete ◽  
Freeze Thaw ◽  
The Core ◽  
Average Compressive Strength

This study investigated the effects of freeze-thaw cycles on the mechanical properties of hardened self-compacting concrete for varying column heights. A column (100×20×300 cm) was fabricated by C30 self-compacting concrete in the laboratory and 10 cube samples (10x10x10 cm) were taken from fresh concrete as the references. After a period of 28 days, 160 core specimens (Ø67 mm in diameter) were taken from different column heights. Unit weight, water absorption, compressive strength, and freeze-thaw tests were performed on these 170 (10 reference cubic and 160 core) samples. The mechanical properties of the core specimens before freeze-thaw and after 8-56 freeze-thaw cycles were reported for varying column heights. The average compressive strength value of the reference cubic samples was determined as 40.28 MPa, while the compressive strengths of the core specimens before freeze-thaw were ranged from 40.25 MPa to 49.62 MPa, impying an increase in compressive strength values up to 23.18% compared to the reference cubic samples. Compressive strengths of the specimens subjected to 8 and 56 freeze-thaw cycles varied between 38.71‒48.07 MPa and 31.72‒39.11 MPa, respectively. Statistical analysis revealed that the compressive strength of the concrete exposed to 56 freeze-thaw cycles was significantly different from that of the other specimens.

ROLE OF THE THYROID GLAND IN DEVELOPMENT AND MAINTENANCE OF RENAL HYPERTENSION IN RATS

1960 ◽  
Vol XXXIV (III) ◽  
pp. 411-429 ◽  
Author(s):  
Melvin J. Fregly ◽  
Kenneth M. Cook
Keyword(s):  
Blood Pressure ◽  
Rate Increase ◽  
Renal Hypertension ◽  
The Other ◽  
Elevated Blood Pressure ◽  
Unit Weight ◽  
Elevated Blood ◽  
Inhibition Of Growth ◽  
Testicular Size

ABSTRACT The anti-thyroid drugs, thiouracil, propylthiouracil, and methimazole, prevented both development of elevated blood pressure and cardiac hypertrophy usually accompanying kidney encapsulation with latex envelopes. These drugs also reduced elevated blood pressure of rats with hypertension of 13 to 40 weeks' duration prior to drug administration. Addition of desiccated thyroid powder to diet containing an anti-thyroid drug overcame the anti-hypertensive effect of the latter. Withdrawal of thyroid powder only was followed by return of blood pressure to previous low level within 3 weeks. The results suggest that the anti-hypertensive effect of these drugs is related directly to the hypothyroidism produced rather than to extrathyroidal effects of the drugs. Comparison of potencies of the 3 drugs in terms of anti-hypertensive effect, inhibition of growth rate, increase in testicular size, and increase in thyroid size suggests that propylthiouracil and methimazole are equally potent per unit weight of drug. Thiouracil has approximately half the potency of the other two.

HAYNES STELLITE ALLOY No. 98M2

Alloy Digest ◽  
1960 ◽  
Vol 9 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Physical Properties ◽  
Room Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
The Other ◽  
Stellite Alloy ◽  
Cobalt Base Alloy ◽  
Cobalt Base

Abstract HAYNES STELLITE 98M2 Alloy is a cobalt-base alloy having higher compressive strength and higher hardness than all the other cobalt-base alloys at room temperature and in the red heat range. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: Co-22. Producer or source: Haynes Stellite Company.

Detection and Assessment of Interleukin 6 in Irreversible Pulp Inflamation

2017 ◽  
Vol 68 (2) ◽  
pp. 323-327
Author(s):  
Cristian Levente Giuroiu ◽  
Maria Vataman ◽  
Gabriel Melian ◽  
Dragos Bularda ◽  
Ludmila Lozneanu ◽  
...  
Keyword(s):  
Dental Caries ◽  
Interleukin 6 ◽  
Dental Pulp ◽  
The Other ◽  
Control Group ◽  
Study Group ◽  
Pulp Tissue ◽  
Immunohistochemical Technique ◽  
Systemic Distribution ◽  
Cell Zone

The study aimed to assess the number, localization and distribution of interleukin 6 (IL-6) positive cells in healthy pulp, acute and chronic pulpitis. The study group included 48 patients aged between 18-72, treated in University of Medicine and Pharmacy Grigore T. Popa Iasi, Romania. The pulpectomy was performed on 42 patients diagnosed with acute and chronic pulpitis. The other 6 patients, without signs of dental caries or periodontal disease, were submitted to extractions of teeth for orthodontic purposes, with pulpectomy performed before extraction. The pulp samples were examined with optic microscope. The detection and assessment of IL-6 were performed using immunohistochemical technique. Data were statistically analysed using non-parametric tests. According to morphopathological criteria, 42.85% were classified as acute pulpitis and 57.14% as chronic pulpitis. The pulp samples in control group were not associated with IL-6 positive cells. The analysis of all samples with acute and chronic pulpitis identified 73.80% samples with IL-6 and 26.20% associated with the absence of IL-6. The highest frequency of IL-6 positive cells was recorded in rich-cell zone of crown dental pulp. The systemic distribution of IL-6 positive cells was mostly diffused without well-defined orientation. IL-6 release in acute and chronic pulpitis is significantly higher comparing with healthy pulp tissue.

Antimicrobial Effect of 940 nm Diode Laser based on Photolysis of Hydrogen Peroxide in the Treatment of Periodontal Disease

2018 ◽  
Vol 69 (8) ◽  
pp. 2081-2088 ◽  
Author(s):  
Alin Alexandru Odor ◽  
Edwin Sever Bechir ◽  
Deborah Violant ◽  
Victoria Badea
Keyword(s):  
Hydrogen Peroxide ◽  
Laser Therapy ◽  
Diode Laser ◽  
Antimicrobial Effect ◽  
The Other ◽  
Control Group ◽  
Group 4 ◽  
Periodontal Bacteria ◽  
Severe Periodontitis ◽  
Before And After

Moderate and severe periodontitis represents a challenge in the non-surgical periodontal therapy. Due to the lack of evidence regarding the antimicrobial effectiveness of 940 nm diode laser in periodontal treatment, this study aimed to evaluate the antimicrobial effect of hydrogen peroxide (H2O2) photolysis performed with 940 nm diode laser in the treatment of moderate and severe periodontitis. Twenty-five patients with 100 teeth were selected for this pilot study. The test teeth were randomly assigned to one of the four treatment groups: Group 1: scaling and root planning (SRP) (control group); and the following experimental groups: Group 2: H2O2; Group 3: 940 nm diode laser therapy; Group 4: 940 nm diode laser therapy and H2O2. Clinical examinations, like probing depth (PD), clinical attachment level (CAL) and bleeding on probing (BOP) were performed before and after the treatment. The microbiological evaluation, effectuated before and after the treatment, included nine periodontal bacteria species and investigated by means of real-time PCR assay. The clinical and bacterial differences in the tested groups, was assessed between control group and the other three experimental groups, as well as between the experimental groups. The total bacteria load was reduced for all four studied groups. Group 4 (diode laser + H2O2) showed significant bacterial reduction of the major periodontal bacteria like Pg., Tf., Td., Pi., Pm., Fn (p[0.001) than the other 3 groups (p]0.001). Also the periodontal clinical parameters, like PD, CAL and BOP showed a significant reduction after the photolysis of H2O2 with the 940 nm diode laser (p[0.001). Differences between tested groups showed a significant beneficial results in regard to Group 4.It is suggested that the photoactivation of H2O2 with the 940 nm diode laser can be used successfully in adjunctive to the non-surgical periodontal treatment as a bactericidal tool.

scholarly journals Psycho-Electrophysiological Benefits of Forest Therapies Focused on Qigong and Walking with Elderly Individuals

2021 ◽  
Vol 18 (6) ◽  
pp. 3004
Author(s):  
Jiyune Yi ◽  
Seul Gee Kim ◽  
Taegyu Khil ◽  
Minja Shin ◽  
Jin-Hee You ◽  
...  
Keyword(s):  
Urban Forest ◽  
Nervous Activity ◽  
Health Problems ◽  
The Other ◽  
Upper Body ◽  
Sympathetic Nervous Activity ◽  
Control Group ◽  
Beta Band ◽  
Elderly Individuals ◽  
Beneficial Effects

We developed two distinct forest therapy programs (FTPs) and compared their effects on dementia prevention and related health problems for older adults. One was focused on Qigong practice in the forest (QP) and the other involved active walking in the forest (WP). Both FTPs consisted of twelve 2-h sessions over six weeks and were conducted in an urban forest. We obtained data from 25, 18, and 26 participants aged 65 years or above for the QP, WP, and control groups, respectively. Neuropsychological scores via cognition (MoCA), geriatric depression (GDS) and quality of life (EQ-5D), and electrophysiological variables (electroencephalography, bioimpedance, and heart rate variability) were measured. We analyzed the intervention effects with a generalized linear model. Compared to the control group, the WP group showed benefits in terms of neurocognition (increases in the MoCA score, and alpha and beta band power values in the electroencephalogram), sympathetic nervous activity, and bioimpedance in the lower body. On the other hand, the QP group showed alleviated depression and an increased bioimpedance phase angle in the upper body. In conclusion, both active walking and Qigong in the forest were shown to have distinctive neuropsychological and electrophysiological benefits, and both had beneficial effects in terms of preventing dementia and relieving related health problems for elderly individuals.

Sign in / Sign up

Export Citation Format

Share Document