Analisa Kekuatan Material pada Aplikasi Dowel Jalan Beton

Jumlah kendaraan yang lewat dengan beban kendaraan melewati batas kuota beban kendaraan yang diperbolehkan melewati jalan tersebut menyebabkan jalan beton mengalami keretakan dan penurunan. Keretakan umumnya terjadi di antara segmen sehingga diperlukan dowel. Tujuan penelitian adalah untuk mengetahui kekuatan dowel sebagai pengait antar segmen beton yang akan berpengaruh terhadap jalan itu sendiri. Material yang digunakan adalah baja dengan diameter 19 mm dan 22 mm. Metode penelitian yang digunakan dalam penelitian ini adalah metode penelitian eksperimen dengan melakukan uji tarik dan uji bending.Hasil pengujian tarik pada dowel diameter 19 mm didapatkan tegangan tarik maksimum sebesar 414,61 N/mm², kekuatan luluh sebesar 291,11 N/mm², dan regangan 23,8%. Sedangkan untuk uji bending pada gaya 15.000 N, tegangan bending sebesar 54,536 MPa. Sedangkan hasil pengujian tarik pada dowel dengan diameter 22 mm didapatkan tegangan tarik maksimum sebesar 565,94 N/mm2, kekuatan luluh sebesar 375,10 N/mm², dan regangan 25,6%. Sedangkan untuk uji bending pada gaya 29.500 N didapatkan tegangan bending sebesar 79,997 MPa.Kesimpulan dalam penelitian ini adalah Nilai kuat tarik untuk kedua baja tersebut tinggi karena melebihi kuat tarik minimum Standar SNI untuk BJPT, yakni 382 N/mm² untuk dowel dengan diameter 19 mm dan 480 N/mm2 untuk dowel dengan diameter 22 mm. Kekuatan material dowel dengan diameter 19 mm mampu menahan beban maksimal 15 ton. Sedangkan kekuatan material dengan diameter 22 mm mampu menahan beban maksimal 30 ton

Quantifying the impact of climate change on drought regimes using the Standardised Precipitation Index

The study presents a methodology to characterise short- or long-term drought events, designed to aid understanding of how climate change may affect future risk. An indicator of drought magnitude, combining parameters of duration, spatial extent and intensity, is presented based on the Standardised Precipitation Index (SPI). The SPI is applied to observed (1955–2003) and projected (2003–2050) precipitation data from the Community Integrated Assessment System (CIAS). Potential consequences of climate change on drought regimes in Australia, Brazil, China, Ethiopia, India, Spain, Portugal and the USA are quantified. Uncertainty is assessed by emulating a range of global circulation models to project climate change. Further uncertainty is addressed through the use of a high-emission scenario and a low stabilisation scenario representing a stringent mitigation policy. Climate change was shown to have a larger effect on the duration and magnitude of long-term droughts, and Australia, Brazil, Spain, Portugal and the USA were highlighted as being particularly vulnerable to multi-year drought events, with the potential for drought magnitude to exceed historical experience. The study highlights the characteristics of drought which may be more sensitive under climate change. For example, on average, short-term droughts in the USA do not become more intense but are projected to increase in duration. Importantly, the stringent mitigation scenario had limited effect on drought regimes in the first half of the twenty-first century, showing that adaptation to drought risk will be vital in these regions

Long-term carbon sink in Borneo's forests halted by drought and vulnerable to edge effects

Less than half of anthropogenic carbon dioxide emissions remain in the atmosphere. While carbon balance models imply large carbon uptake in tropical forests, direct on-the-ground observations are still lacking in Southeast Asia. Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha‾¹ per year (95% CI 0.14—0.72, mean period 1988-2010) above-ground live biomass. These results closely match those from African and Amazonian plot networks, suggesting that the world's remaining intact tropical forests are now en masse out-of-equilibrium. Although both pan-tropical and long-term, the sink in remaining intact forests appears vulnerable to climate and land use changes. Across Borneo the 1997-1998 El Niño drought temporarily halted the carbon sink by increasing tree mortality, while fragmentation persistently offset the sink and turned many edge-affected forests into a carbon source to the atmosphere

Climate knowledge cultures: Stakeholder perspectives on change and adaptation in Nusa Tenggara Barat, Indonesia

Effective climate adaptation requires engagement (awareness, motivation, and capacity to act) at relevant scales, from individuals to global institutions. In many parts of the world, research attention has focused on the engagement of the general public. We suggest that studies also need to focus on key stakeholders in the government and non-governmental sectors who participate in adaptation planning processes, so that a better understanding may be achieved of the distinct knowledge cultures that influence their engagement with climate change. Indonesia is a key actor in climate adaptation because of the potentially dire consequences for its population’s livelihoods and well-being. In this paper we consider whether ‘climate knowledge cultures’ exist amongst stakeholders at multiple organisational levels in Nusa Tenggara Barat (NTB) Province, Eastern Indonesia. Surveys were conducted with 124 stakeholders from differing levels at the beginning of four multi-stakeholder climate adaptation workshops. Questions elicited perceptions of their region’s challenges, observation and awareness of climate change, feelings they associated with climate change, beliefs regarding causes, risks and preparedness for climate change, and timeframes they associated with the future. Across all levels, climate change ranked highest as the first challenge participants identified, followed by food security, but well-being ranked highest when the top three challenges were combined. Most participants believed climate change was happening, but those working at higher organisational levels were more likely to attribute climate change to human factors whereas those at lower levels were more likely to think it was a natural phenomenon. Women were in greater agreement and more optimistic than men about current government policies to cope with climate change. Perceptions differed between sub-districts, reflecting NTB’s climatic diversity. We note that although climate change is an issue of concern among NTB stakeholders, the potential privileging of some knowledge cultures may lead to its association with cultural and political elitism. ​Second, climate change needs to be viewed alongside the myriad other challenges facing NTB, some of which have greater perceived immediacy. This analysis highlights the need for planning that can accommodate and integrate the diverse knowledge cultures and adaptation objectives that exist at multiple levels