ANALISIS KEKUATAN TARIK, KEKERASAN, DAN STRUKTUR MIKRO PADA PENGELASAN SMAW STAINLESS STEEL 312 DENGAN VARIASI ARUS LISTRIK

Penelitian ini bertujuan untuk mengetahui pengaruh variasi arus listrik dengan metode pengelasan SMAW menggunakan arus 70 A, 90 A, dan 110 A. Elektroda yang digunakan adalah E312-16 dengan diameter 3.2 mm. Jenis kampuh yang digunakan adalah kampuh V dengan sudut 600, pengujian yang dilakukan adalah kekuatan tarik, kekerasan, dan struktur mikro. Penelitian ini dilaksanakan di Laboratorium Pengujian Bahan Jurusan Teknik Mesin Fakultas Teknik Universitas Tadulako.Hasil pengujian tarik didapatkan nilai kekuatan tarik pada arus 110 A mempunyai nilai tertinggi yaitu 665,084 Mpa dan terendah 639,680 Mpa, untuk regangan tarik nilai tertinggi pada arus 110 A yaitu 32,72 % dan terendah 30,88 %. Untuk modulus elastisitas dengan arus 70 A memiliki nilai tertinggi yaitu 7282,47 Mpa dan terendah pada arus 110 A yaitu 6719,57 Mpa. Nilai rata-rata kekerasan tertinggi terdapat pada arus 110 A sebesar 221,92 kg/mm2 yang terletak pada daerah logam las. Hasil struktur mikro daerah HAZ mengalami pertumbuhan butir yang meningkat seiring dengan kenaikan Heat Input dan terdapat endapan Karbida Chrom yang lebih sedikit dibandingkan dengan arus yang rendah. Kata Kunci : Arus listrik, SMAW, Stainless Steel 312, kekuatan tarik, kekerasan dan struktur mikr

Revitalising Business Sustainability through Full-Range Leadership Approach: A Supply Chain Management View

The COVID-19 pandemic had a profound impact on small and medium enterprises (SMEs) worldwide, particularly those in emerging economies, disrupting their operations and affecting their sustainability. However, most SMEs were not able to utilize effective leadership to enhance their resilience and navigate the crisis successfully. This study aims to examine the relevance of the Full-Range Leadership Model in understanding the relationship between leadership styles and business sustainability, in the context of operations and supply chain management. The study used a cross-sectional survey approach with a purposive sampling technique to collect data from 214 SMEs in Malaysia. The findings of this study suggest that transformational and transactional leadership styles are significant and positive factors that contribute to business sustainability. On the other hand, laissez-faire leadership is a significant and negative factor that hinders the development of business sustainability and resilience. Therefore, SMEs should incorporate and leverage different leadership styles to strengthen their resilience in the post-pandemic work economy. This study has important implications for SMEs to improve their sustainability and resilience in the face of future crises. By adopting effective leadership styles, SMEs can improve their resilience, build their capacity to adapt to changes and enhance their long-term sustainabilit

Western Tarsier Cephalopachus bancanus at Matang Wildlife Centre, Sarawak

The huge, forward-facing eyes, large ears and small body size immediately identify this animal as a tarsier. The Western Tarsier Cephalopachus bancanus is the only species currently recognized on the island of Borneo: it mainly inhabits lowland areas, but there are montane records up to 1200 metres elevation

Partial mtDNA sequencing data of vulnerable Cephalopachus bancanus from the Malaysian Borneo

Tarsier is an endangered nocturnal primate in the family Tarsiidae and is an endemic to Sundaic islands of Philippine (Carlito syrichta), Sulawesi (Tarsius tarsier-complex) and Borneo (Cephalopachus bancanus). Recent records indicated that most molecular studies were done on the Eastern Tarsier and little information for the other group of tarsiers. Here, we present a partial cytochrome b data set of C. bancanus in Sarawak, Malaysian Borneo. Standard mist nets were deployed at strategic locations in various habitat types. A total of 18 individuals were caught, measured and weighed. Approximately, 2 × 2 mm of tissue samples were taken and preserved in molecular grade alcohol. Out of 18, only 11 samples were screened with partial mtDNA (cytochrome b) and the DNA sequences were registered in the GenBank (accession numbers: KY794797-KY794807). Phylogenetic trees were constructed with 20 additional mtDNA sequences downloaded from GenBank. The data are valuable for the management authorities to regulate the type of management units for the metapopulation to sustain population genetics integrity of tarsiers in the range countries across the Sunda Shelf

An Ecological and Molecular Study of Elusive Western Tarsier Cephalopachus bancanus in Malaysian Borneo

Borneo is one of the biodiversity hotspots that various studies on different taxa have been conducted since lots of endemic species were discovered. The evolution history such as the existence of refugia in Borneo has been identified as the main phenomenon for the high endemism of species. The informations on the ecology and molecular genetics are crucial for better understanding of the current distribution, sociobiology, conservation status and evolution during early stages of primate divergence. The study on the ecology and molecular genetics of the Western Tarsier, Cephalopachus bancanus, was conducted from year 2013 until 2016. A total of 49 individuals of C. bancanus were recorded from Sarawak and Sabah. Based on the results, C. bancanus is mainly found inhabiting mixed dipterocarp forest (MDF), kerangas forest and peat swamp forest. This is most probably due to the plenty of food resources and suitable vegetation conditions provided to C. bancanus. The frequency of the acoustic call for an individual of this species recorded in Mulu NP was 70 kHz. This study showed lack of morphological variations existing between the populations from the southern and central Sarawak. On the contrary, the individual from the northern Sarawak was isolated from that of the southern and central Sarawak. This was probably due to the vegetation and habitat differences and geographical barriers. The D-loop gene of 511 base pairs from a total of 30 individuals of C. bancanus was successfully sequenced. Besides, COI gene with the size of 399 base pairs from a total of 31 individuals of C. bancanus was sequenced. While Cyt b gene with the size of 288 base pairs from 22 individuals of C. bancanus was sequenced. The phylogenetic relationships inferred from these mitochondrial genes showed that all the sequences of C. bancanus in Sarawak formed a monophyletic group. Most of the C. bancanus sequences in Sarawak were in their unique haplotypes. Only individuals from southern and central Sarawak shared the same haplotype groups. The only individual from northern Sarawak population was in its unique haplotype group. There were no phylogeographic patterns being observed in Dloop, COI and Cyt b genes of the sequence samples of C. bancanus in Sarawak. Likewise, less variation observed in the genetic structure of C. bancanus among the population in Sarawak. The habitat fragmentation and habitat loss may restrict the migration of the C. bancanus. Hence, low gene flow was observed among the C. bancanus populations. The estimated divergence time of C. bancanus in Borneo was during the late Miocene epoch which is around 7 Mya. The dispersal of C. bancanus in Borneo is possibly affected by the harsh environment during late Miocene. For future study, more ecological parameters should be added and different molecular markers should be tested

Bats of Bako National Park and Additional Notes on the Rare Partial Albinism in Fawn Roundleaf Bat (Hipposideridae: Hipposideros cervinus)

Bat survey was conducted in Bako National Park from 25th to 29th August 2013. A total of 107 individuals from 11 species of bats were recorded. Hipposideros cervinus was recorded as the most abundance species with 51 individuals while Murina suilla and Rhinolophus affinis were the least abundant with one individual each from total captures. This study has added R. affinis as another new species locality record for the national park. This brings up the total bat species known from the park now to 35 species of bats. Interestingly, an individual of H. cervinus with partial albinism was caught during this survey. This single bat was captured on the 27th August 2013 and will be the first albino bat reported in Borneo and possibly Malaysia. This specimen is an adult female that presents high degree of albinism over most of the body but lacking on the upperparts of the body and part of the wings. Detailed description based on 16 external and craniodental measurements are presented herein along with their species identification through genetic analyses. Further research on the genetic structure and behavior of an albino individual may help to identify the possible causes and consequences of albinism to the bats populations

Small mammals from Miri, northeastern region of Sarawak, Malaysian Borneo: note on new locality records

Small mammal surveys were conducted at Niah National Park, Lambir Hills National Park and Gunung Mulu National Park, Miri Division, in the northeastern region of Sarawak, using ground-level and canopy mist-nets, harp traps, and cage traps. The main objective of these surveys was to assess small mammal diversity in the northeastern region of Sarawak. Gunung Mulu National Park recorded the highest diversity of small mammals with 29 species, followed by Niah National Park with 19 species, and Lambir Hills National Park, 17 species. These surveys revealed nine new locality records for Miri, including eight bat species (Dyacopterus spadiceus, Megaerops wetmorei, Nycteris tragata, Hipposideros cineraceus, Hesperoptenus blanfordi, Kerivoula pellucida, Murina suilla and Myotis muricola)and a squirrel (Sundasciurus brookei). Megaerops wetmorei is also reported for the first time in Sarawak