scholarly journals Elasticity moduli in round wooden beams of Pinus caribaea

2016 ◽  
Vol 36 (3) ◽  
pp. 566-570
Author(s):  
André L. Zangiácomo ◽  
André L. Christoforo ◽  
Francisco A. R. Lahr

ABSTRACT This research aimed at estimating both longitudinal (E) and shear (G) elasticity moduli of round structural-sized beams made of Pinus caribaea timber, verifying thus the validity of the G = E/ 20 relationship established by the Brazilian standard ABNT NBR 7190: 1997 (Designing of Wooden Structures). We tested twenty pieces of green wood with average length, diameter and conicity of 750 cm, 30 cm and 4%, respectively. Two static bending tests were applied at three points of each piece, being nondestructive and using different distances between supports. In the first trial, the length and diameter relationship (L/ d) was set as being equal to 24; yet in the second test, it was set at 12. The elasticity moduli were estimated by a successive use of the Timoshenko beam theory equation, which takes into account the shearing stress effect on displacement calculations. The results of both longitudinal and shear moduli were related through the least square assessment method; thus, we could find a relationship of G = E/ 43. As a result, we observed that the tested wooden pieces are at odds with the Brazilian standards.

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Shuang-Ling Tang ◽  
Yu Wang ◽  
Qi-Ying Xia ◽  
Xue-Hai Ju

Potential energy surface scanning for UC, UN, and UH was performed by configuration interaction (CI), coupled cluster singles and doubles (CCSD) excitation, quadratic configuration interaction (QCISD (T)), and density functional theory PBE1 (DFT-PBE1) methods in coupling with the ECP80MWB_AVQZ + 2f basis set for uranium and 6 − 311 + G∗ for carbon, hydrogen, and nitrogen. The dissociation energies of UC, UN, and UH are 5.7960, 4.5077, and 2.6999 eV at the QCISD (T) levels, respectively. The calculated energy was fitted to the potential functions of Morse, Lennard-Jones, and Rydberg by using the least square method. The anharmonicity constant of UC is 0.0047160. The anharmonic frequency of UC is 780.27 cm−1 which was obtained based on the PBE1 results. For UN, the anharmonicity constant is 0.0049827. The anharmonic frequency is 812.65 cm−1 which was obtained through the PBE1 results. For UH, the anharmonicity constant is 0.017300. The anharmonic frequency obtained via the QCISD (T) results is 1449.8 cm−1. The heat capacity and entropy in different temperatures were calculated using anharmonic frequencies. These properties are in good accordance with the direct DFT-UPBE1 results (for UC and UN) and QCISD (T) results (for UH). The relationship of entropy with temperature was established.


2017 ◽  
Vol 52 (3) ◽  
pp. 395-404
Author(s):  
Xiuqi Lyu ◽  
Jun Takahashi ◽  
Yi Wan ◽  
Isamu Ohsawa

Chopped carbon fiber tape-reinforced thermoplastic material is specifically developed for the high-volume production of lightweight automobiles. With excellent design processability and flexibility, the carbon fiber tape-reinforced thermoplastic material is manufactured by compressing large amounts of randomly oriented, pre-impregnated unidirectional tapes in a plane. Therefore, the carbon fiber tape-reinforced thermoplastic material presents transversely isotropic properties. Transverse shear effect along the thickness direction of carbon fiber tape-reinforced thermoplastic beam has a distinct influence on its flexural deformation. Accordingly, the Timoshenko beam theory combined with vibration frequencies was proposed to determine the set of transverse flexural and shear moduli. Meanwhile, the transverse flexural and shear moduli of carbon fiber tape-reinforced thermoplastic beam were finally determined by fitting all the first seven measured and calculated eigenfrequencies with the least squares criterion. In addition, the suggested thickness to length ratio for the 3-point bending test and Euler–Bernoulli model was given.


2021 ◽  
Vol 2 (4) ◽  
pp. 537-550
Author(s):  
Christina Catur Widayati ◽  
Sarton Sinambela ◽  
Magito Magito ◽  
Khilyatin Ikhsani

The purpose of this study is to find out the factors which affect on purchase decision of fake (non-genuine) Nike sports shoes. Data analysis generally confirms the structural relationship of all variables, namely price and country of origin on brand image and its impact on purchase decision for fake (non-genuine) Nike shoes. This research was conducted on Gold's Gym consumers in the city area of ​​West Jakarta with a sample size of 130 respondents. The data analysis method used in this study is the Component or Variance Based Structural Equation Model where the data processing used Partial Least Square (Smart-PLS) version 3.2.9. The results show that all hypotheses can be accepted, except for the third hypothesis, which indicates that the country of origin does not effect on purchase decision.


Author(s):  
Intan Candradewi ◽  
I Gst. A. Manuati Dewi

The purpose of this study was to analyze and explain the role of mediation motivation in the relationship of compensation to employee performance at Wisma Prashanti Hospital. The population in this study were employees of Wisma Prashanti Hospital with a total sample of 83 respondents. The sampling technique is carried out is a saturated sample technique, the entire population is used as a sample. The research instrument used a questionnaire and analysis method using Partial Least Square (PLS) with SmartPLS 3.2 software. The results showed (1) compensation has a positive and significant effect on employee performance (2) compensation has a positive and significant effect on motivation (3) motivation has a positive and significant effect on employee performance (4) motivation mediates partially and positively and significantly on the relationship between compensation and employee performance. The implications of the results of this study indicate that compensation is found to be a major factor in improving employee performance.


2015 ◽  
Vol 8 (4) ◽  
pp. 134-144
Author(s):  
I.A. Basyul

Hypotheses about the relationship of the processes of visual perception and variations of the task in an identical stimulus environment was tested. The following tasks were tested: 1) a simple observation of the illuminations of the character in the matrix; 2) counting the number of highlights; 3) monitoring of the target symbol highlights and typing text with the P300 BCI. In a group of 14 people showed that the highest average length of visual fixation and the lowest dispersion of fixation observed for the second type of task. Statistically significant differences in the level of dispersion of visual fixations found between 1-2 and 1-3 modes; differences between the modes for the duration of fixations are at trends. Significant differences in the number of visual fixations on the target symbols wasn’t detected. The overall conclusion is the high perspective of pairing methodology brain-computer interface on the P300 wave with eye tracking to optimize the characteristics of the stimulus in the BCI environment. The differences in the parameters of oculomotor activity between the tasks reflect the level of attention concentration in the target symbols of the P300 BCI


Author(s):  
Qingwei Xu ◽  
Kaili Xu ◽  
Fang Zhou

Safety assessment of a casting workshop will provide a clearer understanding of the important safety level required for a foundry. The main purpose of this study was to construct a composite safety assessment method to protect employee health using the cloud model and cause and effect–Layer of Protection Analysis (LOPA). In this study, the weights of evaluation indicators were determined using the subjective analytic hierarchy process and objective entropy weight method respectively. Then, to obtain the preference coefficient of the integrated weight more precisely, a new algorithm was proposed based on the least square method. Next, the safety level of the casting workshop was presented based on the qualitative and quantitative analysis of the cloud model, which realized the uncertainty conversion between qualitative concepts and their corresponding quantitative values, as well as taking the fuzziness and randomness into account; the validity of cloud model evaluation was validated by grey relational analysis. In addition, cause and effect was used to proactively identify factors that may lead to accidents. LOPA was used to correlate corresponding safety measures to the identified risk factors. 6 causes and 19 sub-causes that may contribute to accidents were identified, and 18 potential remedies, or independent protection layers (IPLs), were described as ways to protect employee health in foundry operations. A mechanical manufacturing business in Hunan, China was considered as a case study to demonstrate the applicability and benefits of the proposed safety assessment approach.


2019 ◽  
Vol 7 (4) ◽  
pp. 55 ◽  
Author(s):  
Iman Harymawan ◽  
Mohammad Nasih ◽  
Muhammad Madyan ◽  
Diarany Sucahyati

The purpose of this study is to investigate the relationship of firms with family ownership and their performance in Indonesia and further examine on how political connections affect this relationship. This study used 933 samples from 413 companies listed on the Indonesia Stock Exchange (IDX) in the period between 2014 and 2016. Using ordinary least square (OLS) regression, the results shows that firms without family ownership (non-family firms) have better performance than firms with family ownership (family firms) in Indonesia. Furthermore, the findings also show that the performance of family firms significantly improve when the firms are affiliated with political connections. Our findings imply that establishing political connections in family firms will increase the performance of the firms.


2019 ◽  
Vol 22 ◽  
Author(s):  
Ioannis Nikolaou ◽  
Konstantina Georgiou ◽  
Vasiliki Kotsasarlidou

AbstractOur study explores the validity of a game-based assessment method assessing candidates’ soft skills. Using self-reported measures of performance, (job performance, Organizational Citizenship Behaviors (OCBs), and Great Point Average (GPA), we examined the criterion-related and incremental validity of a game-based assessment, above and beyond the effect of cognitive ability and personality. Our findings indicate that a game-based assessment measuring soft skills (adaptability, flexibility, resilience and decision making) can predict self-reported job and academic performance. Moreover, a game-based assessment can predict academic performance above and beyond personality and cognitive ability tests. The effectiveness of gamification in personnel selection is discussed along with research and practical implications introducing recruiters and HR professionals to an innovative selection technique.


2016 ◽  
Vol 32 (5) ◽  
pp. 515-518 ◽  
Author(s):  
J. A. Franco-Villafañe ◽  
R. A. Méndez-Sánchez

AbstractWe obtain values for the shear coefficient both below and above the critical frequency by comparing the results of the Timoshenko beam theory with experimental data published recently. The best results are obtained, by a least-square fitting, when different values of the shear coefficient are used below and above the critical frequency.


2020 ◽  
Vol 9 (2) ◽  
pp. 35
Author(s):  
Yendraliza Yendraliza ◽  
Muhamad Rodiallah ◽  
Zumarni Zumarni

This study was conducted to determine the relationship of birth weight of calves, sex ratio of the calves, and the age of the dam to the length of pregnancy in buffaloes resulting from artificial insemination in Kampar District. The method used in this research is the descriptive method by displaying the average and standard deviation. The total number of buffaloes that were artificially inseminated in 2018 and gave birth in 2019 was 21 buffalo-cows. Data were analyzed with the Pearson Product Moment (PPM) correlation. The parameters measured in this study were the length of pregnancy, calf birth weight, calf sex ratio, and dam’s age. The results showed a positive correlation between the birth weight of the calves, sex ratio of the calves, and the age of the dam to the length of pregnancy of 1.4%, with an average length of pregnancy, calf birth weight, and sex ratio of 351.81 days, 27.38 kg, and 1: 1 respectively.


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