Assessing low thermal conductivity of bricks which contain rice husk, corn cob and waste tea as an additive material

Energy efficient buildings have emerged as a new approach to encourage use of natural resources and reduction of energy requirements. Thermal and mechanical brick properties play an important role in designing modern buildings. Decreasing thermal conductivity is the dominant factor in reducing heat that could be transferred to or from the building. The main objective of this study is to produce low thermal conductivity brick which helps in improving the surface temperature of the building. Malaysia climate which is 30˚C – 34˚C, exceed the thermal comfort of 26˚C. Excessive heat in the buildings causes discomfort to the occupants. Malaysia produce a vast amount of agricultural waste which is 47, 402 dry/kilotonne/year. It will lead to the disposal problem of these waste materials. Recycling rice husk (RH), waste tea (WT) and corn corb (CC) into fired clay brick can improve thermal conductivity of the existing fired clay brick and reduce waste disposal problem. This study was conducted to identify the effects of using RH, WT and CC on the physical, mechanical and thermal properties of fired clay bricks. The percentage of RH, WT and CC used are 2.5%, 5%, 7.5% and 10%. Standard size of fired clay brick are 215 mm x 102.5 mm x 65 mm. Compressed Stabilized Earth Machine (CSEM) with 900-1000 psi pressure was used in producing these bricks. This study focused on the compressive strength, water absorption and thermal conductivity of the fired clay bricks according to the BS 3921: 1985, MS 76: 1972 and ASTM C518 respectively. Results show that the compressive strength value decrease, water absorption increase and thermal conductivity decrease as the percentage of RH, WT and CC used is increased. However, all the result obtained still complies with the standard used. 7.5% RH (chosen from the low thermal conductivity value and have optimum compressive strength) and control brick (CB) was used to build a small masonry wall sized 1m length x 0.215 m width x 1m height. Result indicates that RH small masonry wall recorded low temperature compared to the CB small masonry wall. Low thermal conductivity bricks can helps in reducing heat absorbed by the bricks and provide better comfort condition to the occupants

Familiarization, Reliability, and Evaluation of a Multiple Sprint Running Test Using Self-Selected Recovery Periods

The aims of the present study were to investigate the process of self-selected recovery in a multiple sprint test with a view to using self-selected recovery time as a means of reliably quantifying an individual's ability to resist fatigue in this type of exercise. Twenty physically active exercise science students (means ± SD for age, height, body mass, body fat, and V̇O2max of the subjects were 21 ± 2 yr, 1.79 ± 0.09 m, 83.7 ± 10.8 kg, 16.6 ± 3.9%, and 52.7 ± 7.2 ml·kg−1·min−1, respectively) completed 4 trials of a 12 × 30 m multiple sprint running test under the instruction that they should allow sufficient recovery time between sprints to enable maximal sprint performance to be maintained throughout each trial. Mean recovery times across the 4 trials were 73.9 ± 24.7, 82.3 ± 23.8, 77.6 ± 19.1, and 77.5 ± 13.9 seconds, respectively, with variability across the first 3 trials considered evidence of learning effects. Test-retest reliability across trials 3 to 4 revealed a good level of reliability as evidenced by a coefficient of variation of 11.1% (95% likely range: 8.0-18.1%) and an intraclass correlation coefficient of 0.76 (95% likely range: 0.40-0.91). Despite no change in sprint performance throughout the trials, ratings of perceived exertion increased progressively and significantly (p < 0.001) from a value of 10 ± 2 after sprint 3 to 14 ± 2 after sprint 12. The correlation between relative V̇O2max and mean recovery time was 0.14 (95% likely range: −0.37-0.58). The results of the present study show that after the completion of 2 familiarization trials, the ability to maintain sprinting performance in a series of repeated sprints can be self-regulated by an athlete to a high degree of accuracy without the need for external timepieces

Refractory hyperparathyroidism with a T3 bony lesion—differential diagnoses

We report a case of severe hyperparathyroidism complicated by osteitis fibrosa cystica in an 83-year-old man post-myocardial infarction. The lesions were evident on magnetic resonance imaging only. A diagnosis of parathyroid carcinoma was considered due to clinical appearance of the parathyroid intraoperatively and the presence of an invasive T3 lesion mimicking metastatic disease. Differentiating parathyroid carcinoma from the benign causes at presentation can be difficult due to overlapping clinical, biochemical, radiological and histological features. The presence of bony lesions increases the diagnostic complexity of the case and demonstrates the challenges involved in the management of this disorder

Hardware extensions to make lazy subscription safe

Abstract Transactional Lock Elision (TLE) uses Hardware Transactional Memory (HTM) to execute unmodified critical sections concurrently, even if they are protected by the same lock. To ensure correctness, the transactions used to execute these critical sections &quot;subscribe&quot; to the lock by reading it and checking that it is available. A recent paper proposed using the tempting &quot;lazy subscription&quot; optimization for a similar technique in a different context, namely transactional systems that use a single global lock (SGL) to protect all transactional data. We identify several pitfalls that show that lazy subscription is not safe for TLE because unmodified critical sections executing before subscribing to the lock may behave incorrectly in a number of subtle ways. We also show that recently proposed compiler support for modifying transaction code to ensure subscription occurs before any incorrect behavior could manifest is not sufficient to avoid all of the pitfalls we identify. We further argue that extending such compiler support to avoid all pitfalls would add substantial complexity and would usually limit the extent to which subscription can be deferred, undermining the effectiveness of the optimization. Hardware extensions suggested in the recent proposal also do not address all of the pitfalls we identify. In this extended version of our WTTM 2014 paper, we describe hardware extensions that make lazy subscription safe, both for SGL-based transactional systems and for TLE, without the need for special compiler support. We also explain how nontransactional loads can be exploited, if available, to further enhance the effectiveness of lazy subscription

DNA Targeting as a Likely Mechanism Underlying the Antibacterial Activity of Synthetic Bis-Indole Antibiotics

We previously reported the synthesis and biological activity of a series of cationic bis-indoles with potent, broad-spectrum antibacterial properties. Here, we describe mechanism of action studies to test the hypothesis that these compounds bind to DNA and that this target plays an important role in their antibacterial outcome. The results reported here indicate that the bis-indoles bind selectively to DNA at A/T-rich sites, which is correlated with the inhibition of DNA and RNA synthesis in representative Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) organisms. Further, exposure of E. coli and S. aureus to representative bis-indoles resulted in induction of the DNA damage-inducible SOS response. In addition, the bis-indoles were found to be potent inhibitors of cell wall biosynthesis; however, they do not induce the cell wall stress stimulon in S. aureus, suggesting that this pathway is inhibited by an indirect mechanism. In light of these findings, the most likely basis for the observed activities of these compounds is their ability to bind to the minor groove of DNA, resulting in the inhibition of DNA and RNA synthesis and other secondary effects