Thermal and Mechanical Properties of Sn-8Zn-3Bi Solder Alloy

Thermal and mechanical properties of Sn-8Zn-3Bi solder alloy on copper substrate were evaluated via measuring the melting temperature, the coefficient of thermal expansion (CTE), the tensile and shear strength of the solder joint. The measured properties of the alloy were then compared to the properties of the traditional and widely used eutectic Sn-37Pb solder alloy. The results show that the melting (liquidus) temperature of Sn-8Zn-3Bi was 195 °C, the CTE of Sn-8Zn-3Bi was 22.2´10-6 K-1 in the temperature range of 30-130 °C. At the same testing condition, both tensile and shear strength of Sn-8Zn-3Bi joints were higher than those of Sn-37Pb. The stress-strain curve indicated that the Sn-8Zn-3Bi joints were brittle whilst the Sn-37Pb joints were ductile.

Test-retest Reliability of the Korean Matrix Sentence-in-noise Recognition in Sound-field Testing Condition

Purpose: This study aimed to measure the test-retest reliability of the Korean Matrix sentence-in-noise test in a sound-field testing condition.Methods: Fifty-five listeners with normal hearing participated. The sound-field speech-in-noise test was administered with a front loudspeaker by presenting noise at a fixed level (65 dB SPL) while adaptively adjusting the sentence level based on the listener’s response. The speech reception thresholds (SRTs) corresponding to 50% sentence-in-noise intelligibility were obtained using speech-shaped noise (SSN), International Collegium of Rehabilitative Audiology (ICRA) noise, and International Speech Test Signal (ISTS) noise. For the test-retest reliability, each subject was tested twice in a 2-week interval. The test-retest reliabilities were judged by the intraclass correlation coefficient (ICC), the minimal detectable change (MDC) values, and Bland-Altman plots.Results: The test-retest reliabilities of the Korean Matrix sentence test were good (ICC, 0.84~0.86) across SSN, ICRA, ISTS noises. The MDC was 0.92 dB SNR for SSN and 2.83 and 2.98 dB SNR for ICRA and ISTS, indicating the random measurement error varied across the types of noise.Conclusion: The Korean Matrix sentence-in-noise test can be used as a reliable tool to assess speech-in-noise intelligibility in sound-field testing condition. Further study across various sessions would strengthen the present finding.

Comparative Assessment of Deformation Under Plate Bearing Test and CBR Test for Subgrade Soil

A significant variation in the strength and deformation behavior of subgrade soil when tested in the laboratory and in the field. However, correlation of such variables is essential to evaluate the quality of the constructed subgrade. An attempt has been made in the present investigation to assess the deformation of control and stabilized subgrade soil in the laboratory and in the field. California bearing ratio (CBR) test was conducted in the laboratory and the static plate bearing test (PBT) was conducted in the field. Subgrade soil samples were stabilized with 6% lime, 17 % Cationic Emulsion, and combination of lime and emulsion. Similar stabilization was conducted at test sections in the field. The behavior of the control and stabilized soil in deformation under static PBT in the field and CBR in the laboratory was monitored and evaluated. It was noticed that polynomial correlation exists with high coefficient of determination between laboratory and field deformation for stabilized soil. It was observed that the deformation under CBR test decreased after implication of lime by (96 and 88) % for unsoaked and soaked testing conditions respectively. The deformation decreases by (92 and 85.6) % for unsoaked and soaked testing conditions respectively when emulsion was implemented. The deformation decreases by (91 and 88) % for unsoaked and soaked testing conditions respectively when combined stabilization was implemented. However, the deformation under PBT decreases by (75, 56, and 50) % for lime, emulsion, and combined stabilization processes respectively. It was concluded that testing condition (soaked or unsoaked) has no significant impact on the deformation of stabilized soil while it has a significant influence on the deformation of untreated soil under CBR test. On the other hand, the deformation of control soil shows no significant variation among field and laboratory testing in the model, however, the stabilized soil samples exhibit higher influence of field deformation on the polynomial models.

Image Quality Assessment to Emulate Experts’ Perception in Lumbar MRI Using Machine Learning

Medical image quality is crucial to obtaining reliable diagnostics. Most quality controls rely on routine tests using phantoms, which do not reflect closely the reality of images obtained on patients and do not reflect directly the quality perceived by radiologists. The purpose of this work is to develop a method that classifies the image quality perceived by radiologists in MR images. The focus was set on lumbar images as they are widely used with different challenges. Three neuroradiologists evaluated the image quality of a dataset that included T1-weighting images in axial and sagittal orientation, and sagittal T2-weighting. In parallel, we introduced the computational assessment using a wide range of features extracted from the images, then fed them into a classifier system. A total of 95 exams were used, from our local hospital and a public database, and part of the images was manipulated to broaden the distribution quality of the dataset. Good recall of 82% and an area under curve (AUC) of 77% were obtained on average in testing condition, using a Support Vector Machine. Even though the actual implementation still relies on user interaction to extract features, the results are promising with respect to a potential implementation for monitoring image quality online with the acquisition process.

Effects of Receiving Genetic Ancestry Results on Emerging Adults’ Ethnic-Racial Identity Affirmation

Ethnic-racial identity (ERI) is associated with adaptive outcomes in emerging adulthood, but more research is needed on factors that may inform ERI, such as receiving one’s genetic ancestry results. The current study examined changes in ERI using a pre-test post-test design in which 116 emerging adults 18–25 years were randomly assigned to either receiving their genetic ancestry results before the post-test (the testing condition) or after post-test (the control condition). We also tested whether ethnicity/race and gender moderated these associations. Findings indicated that male students of color (SOC) in the testing condition experienced an increase in ERI affirmation from pre-test to post-test, and male SOC in the control condition experienced a decrease in ERI affirmation from pre-test to post-test. There were no significant differences in ERI affirmation change between students in the testing condition and control condition for female SOC, White males, or White females.

Preliminary Design of Wellhead Spacer Spool Based On the API Acceptance Criteria

In the case of assembly wellhead, a spacer spools was used to provide space and connect between parts of the wellhead. In order to design spacer spool with specified material should comply the standards and procedures of the oil and gas industry. The results of the material calculation were using the ASME BPVC guidelines. These three materials strengths were calculated if used as a body spacer spool. Based on acceptance criteria on API 6A 21st Edition, these three materials were categorized as acceptable to be used as a body spacer spool for this specification. These three materials strengths were also calculated the stress of the flange and flange rigidity criteria. Based on the acceptance criteria on ASME BPVC guidelines, the results showed that these materials can be used for flange because it had stress value under yield strength of material which was flange rigidity criteria for operating condition has 0.59 and 0.66 for testing condition because had value of rigidity that met with minimum acceptance criteria.

Interleaved practice benefits implicit sequence learning and transfer

Compared to blocked practice, interleaved practice of different tasks leads to superior long-term retention despite poorer initial acquisition performance. This phenomenon, the contextual interference effect, is well documented in various domains but it is not yet clear if it persists in the absence of explicit knowledge in terms of fine motor sequence learning. Additionally, while there is some evidence that interleaved practice leads to improved transfer of learning to similar actions, transfer of implicit motor sequence learning has not been explored. The present studies used a serial reaction time task where participants practiced three different eight-item sequences that were either interleaved or blocked on Day 1 (training) and Day 2 (testing). In Experiment 1, the retention of the three training sequences was tested on Day 2 and in Experiment 2, three novel sequences were performed on Day 2 to measure transfer. We assessed whether subjects were aware of the sequences to determine whether the benefit of interleaved practice extends to implicitly learned sequences. Even for participants who reported no awareness of the sequences, interleaving led to a benefit for both retention and transfer compared to participants who practiced blocked sequences. Those who trained with blocked sequences were left unprepared for interleaved sequences at test, while those who trained with interleaved sequences were unaffected by testing condition, revealing that learning resulting from blocked practice may be less flexible and more vulnerable to testing conditions. These results indicate that the benefit of interleaved practice extends to implicit motor sequence learning and transfer.