Analisis Perbandingan Komposisi Karbon Dan Bubuk Tulang Sapi Dalam Proses Karburasi Padat Untuk Mendapatkan Nilai Kekerasan Tertinggi Pada Baja Karbon S-35 C

S-35 C, is a low steel carbon type with 0,30% - 0,35% carbon composition, which has a low hardness. This matter can be overcome by changing the hardness of this steel through heat treatment process. Heat treatment method used in this experiment is pack carburizing method. Experiment results showed that with composition of 500 g of carbon and 0% beef bones with 15 minutes holding time, the hardness number increased as much as 116.90 HRC, there was 20.54 HRC number increased. With 10% of cow bones composition, hardness number became 118.39 HRC and 20.40 HRC number increased. HRC number became 122.20 and increased by 24.38 on 20% composition, and on 30% the hardness value became 130.36 HRC, increased until 32.05 HRC number. 40% composition showed increasing hardness number up to 133.34 HRC, with 35.08 HRC increased. And 50% composition showed 141.29 HRC number, increased until 43.95 HRC. 50% composition produce the highest increase of hardness number, this verified that the higher composition of cow bones makes higher increasing of hardness number in a heat treatment process deliver a harder steel, and also prove that beef bones can be used as a catalyst in pack carburizing process

PENGARUH PENGUJIAN KEKERASAN DAN PENGUJIAN TEKAN TERHADAP KARAKTERISTIK GAYA TUMBUKAN PADA CANGKANG KENARI (CANARIUM INDICUM L)

Kenari (Canarium indicum L) belongs to the Burseraceae family and is one of the endemic fruits in Indonesia, especially Maluku. Walnuts have a tough shell that encloses the flesh, to get the flesh without damaging it careful effort is needed. This study investigated the strength of walnut shells through mechanical testing to determine the amount of impact force needed to break the walnut shell. The mechanical test carried out is a compression test and impact test. The values of these tests assist in determining, measuring, and analyzing the minimum and maximum force loads required to crack a walnut shell. Tests were carried out on walnut shells from 6 different villages on Ambon Island and Saparua Island. The impact test where the highest impact absorption energy value was found in walnut shells from Booi Village, namely 23.18 J/mm2, and the lowest in walnut shells from Morela Village, 22.40 J/mm2. In the compression test where the lowest value was found in walnut shells from Morela village with a value of 3.61 MPa while the highest value was found in walnut shells from Booi village, namely 5.24 MPa. Whereas the minimum compressive force is 16.22 kgf/mm2 and the maximum compressive force is 17.61 kgf/mm2

Incidental and Underreported Pleural Plaques at Chest CT: Do Not Miss Them - Asbestos Exposure Still Exists

Pleural plaques (PPs) may be a risk factor for mortality from lung cancer in asbestos-exposed workers and are considered to be a marker of exposure. Diagnosing PPs is also important because asbestos-exposed patients should be offered a health surveillance that is mandatory in many countries. On the other hand PPs are useful for compensation purposes. In this study we aimed to evaluate the prevalence, as incidental findings, and the underreporting rate of PPs in chest CT scans (CTs) performed in a cohort of patients (1512) who underwent chest CT with a slice thickness no more than 1.25 mm. PPs were found in 76 out of 1482 patients (5.1%); in 13 out of 76 (17,1%) CTs were performed because of clinical suspicion of asbestos exposure and 5 of them (38%) were underreported by radiologist. In the remaining 63 cases (82.9%) there was no clinical suspicion of asbestos exposure at the time of CTs (incidental findings) and in 38 of these 63 patients (60.3%) PPs were underreported. Reaching a correct diagnosis of PPs requires a good knowledge of normal locoregional anatomy and rigorous technical approach in chest CT execution. However the job history of the patient should always be kept in mind

Validation of a multifactorial risk factor model used for predicting future caries risk with nevada adolescents

<p>Abstract</p> <p>Background</p> <p>The objective of this study was to measure the validity and reliability of a multifactorial Risk Factor Model developed for use in predicting future caries risk in Nevada adolescents in a public health setting.</p> <p>Methods</p> <p>This study examined retrospective data from an oral health surveillance initiative that screened over 51,000 students 13-18 years of age, attending public/private schools in Nevada across six academic years (2002/2003-2007/2008). The Risk Factor Model included ten demographic variables: exposure to fluoridation in the municipal water supply, environmental smoke exposure, race, age, locale (metropolitan vs. rural), tobacco use, Body Mass Index, insurance status, sex, and sealant application. Multiple regression was used in a previous study to establish which significantly contributed to caries risk. Follow-up logistic regression ascertained the weight of contribution and odds ratios of the ten variables. Researchers in this study computed sensitivity, specificity, positive predictive value (PVP), negative predictive value (PVN), and prevalence across all six years of screening to assess the validity of the Risk Factor Model.</p> <p>Results</p> <p>Subjects' overall mean caries prevalence across all six years was 66%. Average sensitivity across all six years was 79%; average specificity was 81%; average PVP was 89% and average PVN was 67%.</p> <p>Conclusions</p> <p>Overall, the Risk Factor Model provided a relatively constant, valid measure of caries that could be used in conjunction with a comprehensive risk assessment in population-based screenings by school nurses/nurse practitioners, health educators, and physicians to guide them in assessing potential future caries risk for use in prevention and referral practices.</p

Recolonizing carnivores: Is cougar predation behaviorally mediated by bears?

Conservation and management efforts have resulted in population increases and range expansions for some apex predators, potentially changing trophic cascades and foraging behavior. Changes in sympatric carnivore and dominant scavenger populations provide opportunities to assess how carnivores affect one another. Cougars (Puma concolor) were the apex predator in the Great Basin of Nevada, USA, for over 80 years. Black bears (Ursus americanus) have recently recolonized the area and are known to heavily scavenge on cougar kills. To evaluate the impacts of sympatric, recolonizing bears on cougar foraging behavior in the Great Basin, we investigated kill sites of 31 cougars between 2009 and 2017 across a range of bear densities. We modeled the variation in feeding bout duration (number of nights spent feeding on a prey item) and the proportion of primary prey, mule deer (Odocoileus hemionus), in cougar diets using mixed-effects models. We found that feeding bout duration was driven primarily by the size of the prey item being consumed, local bear density, and the presence of dependent kittens. The proportion of mule deer in cougar diet across all study areas declined over time, was lower for male cougars, increased with the presence of dependent kittens, and increased with higher bear densities. In sites with feral horses (Equus ferus), a novel large prey, cougar consumption of feral horses increased over time. Our results suggest that higher bear densities over time may reduce cougar feeding bout durations and influence the prey selection trade-off for cougars when alternative, but more dangerous, large prey are available. Shifts in foraging behavior in multicarnivore systems can have cascading effects on prey selection. This study highlights the importance of measuring the impacts of sympatric apex predators and dominant scavengers on a shared resource base, providing a foundation for monitoring dynamic multipredator/scavenger systems

Sickle cell disease: continuous arterial spin-labeling perfusion MR imaging in children

Cerebral blood flow (CBF) was measured with continuous arterial spin-labeling perfusion magnetic resonance (MR) imaging in 14 children with sickle cell disease and seven control subjects. Mean CBF values were higher in patients (P &lt;.005) than in control subjects in all cerebral artery territories. Three patients had decreased CBF in right anterior and middle cerebral artery territories compared with CBF on the left, and one patient had a profound decrease in CBF in all three territories in the right hemisphere. Base; line CBF was significantly decreased in territories seen as unaffected on conventional MR images and MR angiograms in four children with sickle cell disease

Sickle cell disease: continuous arterial spin-labeling perfusion MR imaging in children.

Cerebral blood flow (CBF) was measured with continuous arterial spin-labeling perfusion magnetic resonance (MR) imaging in 14 children with sickle cell disease and seven control subjects. Mean CBF values were higher in patients (P \u3c .005) than in control subjects in all cerebral artery territories. Three patients had decreased CBF in right anterior and middle cerebral artery territories compared with CBF on the left, and one patient had a profound decrease in CBF in all three territories in the right hemisphere. Baseline CBF was significantly decreased in territories seen as unaffected on conventional MR images and MR angiograms in four children with sickle cell disease