Uji Model Dinding Penahan Tanah dengan Timbunan Gambut Menggunakan Perkuatan Fleksibel Terpal

Kebutuhan konstruksi penahan yang digunakan untuk mencegah terjadinya kelongsoran menurut kemiringan alaminya semakin hari bertambah luas, hal inilah yang mendasari dibuatnya konstruksi dinding penahan tanah pada tanah gambut. Permasalahan yang timbul bilamana akan membangun diatas lapisan tanah gambut adalah terbatasnya informasi mengenai perilaku dan cara memperkirakan pemampatan serta metode Perubahan lapisan tanah gambut, oleh sebab itu digunakan perkuatan fleksibel terpal karena lebih ekonomis dan mudah didapatkan.Pengujian ini bertujuan untuk mengetahui besarnya pengaruh variasi lebar perkuatan (LR) dengan Spasi antar perkuatan (SV) yang sama (perkuatan fleksibel terpal yang tertancap didinding penahan tanah) dalam timbunan tanah gambut. Metodologi peneltian yang digunakan adalah pengujian dengan skala laboratorium. Data yang diperoleh dari pengujian tersebut kemudian dianalisa sehingga didapatkan tegangan lateral minimum, pergeseran minimum dan beban maksimum pada setiap variasi perkuatan. Hasil penelitian ini menunjukkan bahwa setiap variasi lebar perkuatan memiliki batasan maksimum masing-masing dalam menerima pembebanan, pergeseran serta tegangan lateral yang terjadi, apabila pembebanan diteruskan maka pergeseran dan tegangan lateral akan konstan (tidak berubah). Pemberian perkuatan dapat mempengaruhi besarnya tegangan lateral minimum dengan nilai 0,01014 kg/cm2, pergeseran minimum dengan nilai 38,2 mm serta pembebanan maksimum yang dapat ditahan oleh dinding penahan tanah tersebut dengan nilai maksimum 270 kg

Pengaruh Powder Factor Peledakan Terhadap Produktivitas Backhoe Komatsu Pc 2000 Di Pt.bukit Asam (Persero)tbk

PT.Pama Persada Nusantara sebagai kontraktor pemboran dan peledakan pada lapisan interburden B2C Pit Pre-Bench pada bulan Oktober - November 2013 mengalami penurunan nilai powder factor dibawah standar PT.Bukit Asam (Persero)Tbk. Powder factor standar PT.Bukit Asam (Persero)Tbk sebesar 0,19 kg/m3 - 0,24 kg/m3. Nilai powder factor diturunkan menjadi 0,11 kg/m3 - 0,17 kg/m3 akibatnya menimbulkan pengaruh terhadap persentase fragmentasi ukuran > 100 cm, nilai digging time serta produktivitas Backhoe Komatsu PC 2000 tidak tercapai. Ketidaktercapain produktivitas tersebut dianalisis nilai fragmentasinya berdasarkan metode Kuzram (1973), digging time, dan produktivitasnya kemudian setelah dianalisis mencari nilai rekomendasi powder factor untuk mecapai target produktivitas. Analisis powder factor 0,11 kg/m3 – 0,17 kg/m3 secara berurutan hasil fragmentasi ukuran >100 cm adalah 32,65%, 34,22%, 33,93%, 32,32%, 27,41%, 27,1 %, 25,2 %, hasil digging time secara berurutan 17,35 detik, 17,27 detik, 16,56 detik, 16,12 detik, 14,23 detik, 13,04 detik, dan hasil produktivitas secara berurutan 551,817 bcm/jam, 574,273 bcm/jam, 579,817 bcm/jam, 600,253 bcm/jam, 665,406 bcm/jam, pada hasil analisis powder factor 0,11 kg/m3 – 0,17 kg/m3 diatas fragmentasi tidak ada yang dibawah 15 %, digging time tidak optimal dan target produktivitas tidak ada yang tercapai tercapai 750 bcm/jam. Jadi, untuk mencapai target produktivitas 750 bcm/jam dihitung dengan persamaan regresi linier rekomendasi powder factornya 0,22 kg/m3 dengan digging time 10,29 detik, dan untuk perbaikan geometri peledakan menggunakan persamaan RL. ASH (1990) agar fragmentasi dibawah 15 % menghasilkan burden 6 m, spasi 7 m, powder charge 4,25 m, stemming 3,45 m, subdrilling 0,3 m, kedalaman lubang ledak 8 m, dan tinggi jenjang 7,7 m dan menghasilkan powder factor 0,24 kg/m3 dengan persentase fragmentasi ukuran >100 cm sebesar 13,17 %. Maka powder factor yang direkomendasikan adalah 0,22 kg/m3– 0,24 kg/m

Validasi Metode Analisis Logam Na, K, Mg Dan Ca Pada Air Tua (Bittern) Menggunakan Microwave Plasma-atomic Emission Spectrometer (Mp-aes)

This research aims to obtain analysis method for mayor elements (Na, K, Mg, and Ca) in bittern using Microwave Plasma-Atomic Emission Spectrometry (MP-AES) and to assess the validity of the obtained method. It is known that sea bittern characteristic has complex matrix for its high concentration of the inorganic materials. Therefore assessment of the validity of the analytical method for mayor element is important. The performance characteristics of the method were established by multi-elements-standard-solution assay (Na, K, Mg and Ca), in which samples were un-spiked. Selectivity, linearity, accuracy, precision, detection and quantification limit of the method were evaluated in the study. Matrix effects were not significantly identified for the studied elements. Linearity of selected concentration range for Na, K, Mg and Ca varied from 0.9955- 0.9998. No deviation of true value for all elements was observed in the accuracy test. Meanwhile, precision values of the method (%RSD) were 1.491; 2.702; 2.678; and 1.923, respectively for Na, K, Mg and Ca. The method developed in the present study indicated the detection limits for Na, K, Mg and Ca were 0,184; 0,070; 0,219 dan 0,005 mg/l, respectively, with quantification limits of 0,613; 0,230; 0,730 dan 0,017mg/l. The results of the validation method showed that the proposed method is selective and feasible for sea bittern analysis using MP-AES

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

BackgroundEstimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period.Methods22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution.FindingsGlobal all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations.InterpretationGlobal adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic