Carbonation depth in 57 years old concrete structures

Ronaldo A. Medeiros-Junior,Maryangela G. Lima,Ricardo Yazigi,Marcelo H.F. Medeiros 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.4

Carbonation depth was verified in 40 points of two 57 years old concrete viaducts. Field testing (phenolphthalein spraying) was performed on the structures. Data obtained were statistically analyzed by the Kolmogrov-Smirnov's test, one-way analysis of variance (ANOVA's test), and Fisher's method. The results revealed significant differences between maximum carbonation depths of different elements of the same concrete structure. Significant differences were also found in the carbonation of different concrete structures inserted in the same macroclimate. Microclimatic factors such as temperature and local humidity, sunshine, wind, wetting and drying cycles, among others, may have been responsible by the behavior of carbonation in concrete.

Double controller of wind induced bending oscillations in telecom towers

Ronaldo C. Battista,Michèle S. Pfeil,Eliane M.L. Carvalho,Wendell D. Varela 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.21 No.1

Wind induced large bending oscillation amplitudes in tall and slender telecommunication steel towers may lead to precocious fatigue cracks and consequent risk of collapse of these structures, many of them installed in rural areas alongside highways and in highly populated urban areas. Varying stress amplitudes at hot spots may be attenuated by means of passive control mechanical devices installed in the tower. This paper gives an account of both mathematical-numerical model and the technique applied to design and evaluate the performance of a double controller installed in existing towers which is composed by a nonlinear pendulum and a novel type of passive controller described herein as a planar motion disk mounted on shear springs. Results of experimental measurements carried out on two slender tubular steel towers under wind action demonstrate the efficiency of the double controllers in attenuating the towers bending oscillation amplitudes and consequent stress amplitudes extending the towers fatigue life.

A system of multiple controllers for attenuating the dynamic response of multimode floor structures to human walking

Ronaldo C. Battista,Wendell D. Varela 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.5

Composite floor structures formed by continuous slab panels may be susceptible to excessive vibrations, even when properly designed in terms of ultimate limit state criteria. This is due to the inherent vibration characteristics of continuous floor slabs composed by precast orthotropic reinforced concrete panels supported by steel beams. These floor structures display close spaced multimode vibration frequencies and this dynamic characteristic results in a non-trivial vibration problem. Structural stiffening and/or insertion of struts between floors are the usual tentative solution applied to existing vibrating floor structures. Such structural alterations are in general expensive and unsuitable. In this paper, this vibration problem is analyzed on the basis of results obtained from experimental measurements in typical composite floors and their theoretical counterpart obtained with computational modeling simulations. A passive control system composed by multiple synchronized dynamic attenuators (MSDA) was designed and installed in these floor structures and its efficiency was evaluated both experimentally and through numerical simulations. The results obtained from experimental tests of the continuous slab panels under human walking dynamic action proved the effectiveness of this control system in reducing vibrations amplitudes.

Double controller of wind induced bending oscillations in telecom towers

Battista, Ronaldo C.,Pfeil, Michele S.,Carvalho, Eliane M.L.,Varela, Wendell D. Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.1

Wind induced large bending oscillation amplitudes in tall and slender telecommunication steel towers may lead to precocious fatigue cracks and consequent risk of collapse of these structures, many of them installed in rural areas alongside highways and in highly populated urban areas. Varying stress amplitudes at hot spots may be attenuated by means of passive control mechanical devices installed in the tower. This paper gives an account of both mathematical-numerical model and the technique applied to design and evaluate the performance of a double controller installed in existing towers which is composed by a nonlinear pendulum and a novel type of passive controller described herein as a planar motion disk mounted on shear springs. Results of experimental measurements carried out on two slender tubular steel towers under wind action demonstrate the efficiency of the double controllers in attenuating the towers bending oscillation amplitudes and consequent stress amplitudes extending the towers fatigue life.

Factors affecting university entrants’ performance in high-stakes tests: a multiple regression analysis

Chin Uy,Ronaldo A. Manalo,Ronaldo R. Cabauatan 서울대학교 교육연구소 2015 Asia Pacific Education Review Vol.16 No.4

In the Philippines, students seeking admission to a university are usually required to meet certain entrance requirements, including passing the entrance examinations with questions on IQ and English, mathematics, and science. This paper aims to determine the factors that affect the performance of entrants into business programmes in high-stakes test. Three groups of factors were considered: personal, family, and school factors. A total of 1,057 freshmen enrolled in a business college in academic year 2013–2014 answered a researcher-developed instrument to capture data, which were analysed using multiple regression analysis. Academic library use, reading, and involvement in extra-curricular activities among the personal factors; family size, socio-economic status, and parental involvement among the family factors were found to have significant relationship with entrance test results. As to school factors, the type of school affects entrants’ performance in the test.

영성 생활로 자신을 살아가기

로널드 롤하이저 가톨릭대학교 사목연구소 2003 司牧硏究 Vol.11 No.-

Performance Evaluation of Disruption Tolerant Networks on Warships’ Tactical Messages for Secure Transmissions

Davi Falcão,Ronaldo Salles,Paulo Maranhão 한국통신학회 2021 Journal of communications and networks Vol.23 No.6

Disruption tolerant networks (DTN) are an evolutionof mobile adhoc networks (MANET) working in scenarios wherenodes are sparsely distributed, with low density, connectionsare intermittent and end-to-end infrastructure is not accessible. Therefore, DTNs are recommended for high latency applicationsthat can last from hours to days. The maritime scenario hascharacteristics that would justify the use of DTN networks,but the concern with data security is also a relevant aspectin such scenarios. Thus, this paper proposes to evaluate theDTN approach in the maritime Scenario involving warships andhelicopters, for sending tactical messages, taking into considerationsecurity aspects at the perimeters where contacts occur. Weset up a simulation experiment to compare the performance ofEpidemic, Spray and Wait, and Direct Delivery protocols in threescenarios with different sizes. We also propose the application ofdiscriminant analysis as a classification technique to select secureconnections to improve the security of the DTN architecture.

Grain Growth Behavior and Improved Mathematical Model of a New-Type Superalloy

Zhang Haoqiang,Ronaldo Juanatas,Jasmin Niguidula,Jonathan M. Caballero,Cai Liu 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.1

The grain growth at high temperature significantly affects the ultimate grain sizes and mechanical properties of superalloy. To study the grain growth behavior of a new-type nickel-base superalloy, GH4065 alloy, a series of grain growth tests within the holding temperature range of 1100–1350 K and holding time range of 0–14,400 s were conducted. Via the morphology analysis, it was concluded that the grains of GH4065 alloy normally grow during the temperature range of 1100–1250 K and abnormally grow during the temperature range of 1300–1350 K. The average grain sizes at different experimental conditions were counted and the influences of holding temperature and holding time on the average grain sizes of GH4065 alloy were investigated. It was revealed that the grain sizes increase but the grain growth rates gradually slow down with the increase of holding time; the grain sizes increase with the holding temperature increase and higher temperature further promotes the grain growth degree. Based on the Sellar-type and Anelli-type grain growth mathematics model, an improved two-segment grain growth model was developed and computed to describe the grain growth behavior of GH4065 alloy at high temperature. The evaluation results show that the constructed grain growth model possesses high prediction precision in grain growth behavior characterization of GH4065 alloy.

Acupuncture in the Management of Acute Dental Pain

Ca´ssia Maria Grillo,Ronaldo Seichi Wada,Maria da Luz Rosa´rio de Sousa 사단법인약침학회 2014 Journal of Acupuncture & Meridian Studies Vol.7 No.2

Acute dental pain is the main reason for seeking dental services to provide urgent dental care; there is consensus about the use of alternative therapies, such as acupuncture, to control dental pain in pre-dental care. This study aimed to evaluate the use of acupunc- ture in reducing the intensity of acute dental pain in pre-dental care in patients waiting for emergency dental care, and was conducted at the After-Hours Emergency Dental Clinic of Piracicaba Dental School, and at the Emergency Center Dental Specialties I in Piracicaba, Sa ˜o Paulo, Brazil. The sample consisted of 120 patients. The Visual Analog Scale (VAS) was used to measure pain intensity. All patients underwent one session of acupuncture; the points LI4, ST44 and CV23 were selected and were used alone or in com- binations. Reduction in pain was observed in 120 patients (mean initial VAS = 6.558 ± 1.886, p < 0; mean final VAS= 0.962 ± 2.163, p < 0.00001). The results of this study indi- cate that acupuncture analgesia could be a technical adjunct to pain control in patients with acute dental pain, contributing to the restoration of health with social benefit.

Preliminary Study on Meat Quality of Goats Fed Levels of Licury Oil in the Diet

Silva, Thadeu Mariniello,Oliveira, Ronaldo Lopes,Barbosa, Larissa Pires,Neto, Americo Froes Garcez,Bagaldo, Adriana Regina,Lanna, Dante Pazzanese Duarte,Da Silva, Mauricio Costa Alves,De Jesus, Iona B Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.8

The study aimed to evaluate the best level of licury oil in the diet of 3/4 Boer goats, as determined by profile analysis of commercial cuts on aspects of chemical composition, sensorial quality and fatty acid content. Nineteen male goats were used, with an initial weight of 10.8 kg/live weigh. The animals were fed with hay and a concentrated mix containing different levels of licury oil, which constituted the treatments. The experiment lasted for 60 days, at which point the animals were submitted to feed fasting and slaughtered. The carcass weight, commercial yield and cuts were measured. The ham was collected for sensorial and chemical evaluation and the longissimus dorsi was collected for fatty acid profile analysis. The addition of licury oil to the diet did not promote changes in the proportions and weights of the commercial cuts, nor to the meat's sensorial attributes. The sum of medium-chain fatty acids and the atherogenicity index was increased with the addition of oil. Licury oil can be added to the diet of goats (up to 4.5%) without resulting in changes in to the proportions of the commercial cuts, or to the chemical composition or sensorial characteristics of the meat. Based on the chain length of fatty acids, the addition of 4.5% licury oil can improve the quality of meat, but no effect was noted in relation to the atherogenicity index.