scholarly journals Kajian Performansi Pompa Slurry pada Bucket Wheel Dredger dengan Variasi Sudut Gali 45°, 50° dan 55°

2018 ◽  
Vol 1 (1) ◽  
pp. 001-006
Author(s):  
Billy Emkel Gudsanov ◽  
Tekad Sitepu
Keyword(s):  
Operating Conditions ◽  
Mining Method ◽  
Bernoulli Equation ◽  
Optimal Operating ◽  
Cross Sectional ◽  
Mining Company ◽  
Flow Capacity ◽  
The World ◽  
Depth Study ◽  
Offshore Mining

PT.Timah (Persero) Tbk. merupakan perusahaan tambang timah dengan cadangan timah terbesar di dunia yang menggunakan kapal keruk tipe Bucket Wheel Dredger sebagai salah satu metode penambangan lepas pantai. Proses penambangan ini membutuhkan biaya yang besar, tetapi akibat kondisi operasi yang tidak optimal, dibutuhkan waktu dan biaya lebih dalam proses penambangannya. Oleh karena itu diperlukan kajian yang lebih mendalam untuk mengetahui kondisi operasi optimal. Dalam penelitian ini, peneliti melakukan perhitungan head secara teoritis dimana prosedur dimulai dengan pengumpulan data data pendukung, kemudian melakukan perhitungan untuk mendapatkan hasil. Untuk mendapatkan nilai head, digunakan persamaan Bernoulli. Untuk kerugian head major dan head minor digunakan persamaan Darcy-Weisbach. Kapasitas aliran adalah tetap sebesar 7747.2 m3/h padatan dengan variasi sudut gali 45°, 50°, dan 55° pada luas penampang pemakaian baru, satu bulan, dua bulan, dan tiga bulan. Setelah didapat besar head, didapat putaran optimum pompa untuk sudut operasi 45°, 50°, dan 55° secara berurutan adalah 522.470 rpm, 523.569 rpm, dan 524.550 rpm untuk pemakaian baru, 522.614 rpm, 523.706 rpm, dan 525.690 rpm untuk pemakaian satu bulan, 521.829 rpm, 522.931 rpm, dan 523.917 rpm untuk pemkaian dua bulan, 521.030 rpm, 522.122 rpm dan 523.142 rpm untuk pemakaian tiga bulan.   PT. Timah (Persero) Tbk. is a tin mining company with the largest tin reserve in the world which operates Bucket Wheel Dredger as an offshore mining method. This mining process requires a large amount of cost. It needs more time and cost in mining process due to non-optimal operating conditions. Therefore, a more in-depth study is needed to determine the optimal operating conditions. In this study, the researcher performed theoretical head calculations where the procedure began by collecting supporting data, then performing calculations to obtain the results. Bernoulli equation was used to get the head value, whereas, Darcy-Weisbach equation was used for the loss of major head and minor head. The flow capacity was fixed at 7747.2 m3/h solid with the variations of digging angles of 45°, 50°, and 55° on the cross-sectional area for new, one month, two months, and three months usages. After obtaining a head value, the optimum pump rotations obtained for operating angles of 45 °, 50 °, and 55 ° respectively are 522,470 rpm, 523,569 rpm, and 524,550 rpm for new usage, 522,614 rpm, 523,706 rpm and 525,690 rpm for one month usage, 521,829 rpm, 522,931 rpm, and 523,917 rpm for two months usage, 521,030 rpm, 522.122 rpm and 523,142 rpm for three months usage.

scholarly journals Analisa Titik Operasi Optimum Pompa Slurry pada Bucket Wheel Dredger dengan Variasi Sudut Gali 30°, 35° dan 40°

2018 ◽  
Vol 1 (1) ◽  
pp. 034-039
Author(s):  
Robby Christian ◽  
Tekad Sitepu
Keyword(s):  
Optimum Operating ◽  
Cross Sectional ◽  
Mining Company ◽  
Flow Capacity ◽  
Operating Process ◽  
Piping Networks ◽  
Tin Metal ◽  
Filtration Unit ◽  
Optimum Operating Point ◽  
Offshore Mining

PT.Timah (Persero) Tbk. merupakan perusahaan tambang timah dengan cadangan terbesar di dunia yang menggunakan kapal isap tipe Bucket Wheel Dredger sebagai salah satu metode penambangan lepas pantai. Untuk mendistribuskan material tambang dari dasar laut menuju unit penyaringan, digunakan air sebagai media pembawa dibantu dengan pompa melalui jaringan pemipaan. Pada proses pengerukan, ternyata didapat masih ada material logam timah yang tertinggal di dasar lautan. Hal ini menyebabkan pengerukan menjadi kurang maksimal. Oleh karena itu, diperlukan analisa untuk mencari kondisi operasi optimum untuk setiap kedalaman penggalian. Dalam penelitian ini, dilakukan perhitungan head secara teoritis dimana prosedur dimulai dengan pengumpulan data pendukung, kemudian melakukan perhitungan untuk mendapatkan hasil. Dalam kondisi lapangan, didapat perubahan luas penampang pipa dikarenakan erosi. Untuk menghitung head, digunakan persamaan Bernoulli, untuk kerugian head major dan head minor digunakan persamaan Darcy-Weisbach dimana kapasitas aliran adalah tetap 7747.2 m3/h dengan variasi sudut gali 30°,35°, dan 40° pada luas penampang dengan pemakaian baru, 1 bulan, 2 bulan, dan 3 bulan. Didapat titik operasi optimum pompa slurry untuk setiap sudut secara berurutan adalah pada 517.08 rpm, 517.44 rpm, 520.96 rpm untuk pemakaian baru; 517.44 rpm, 517.44 rpm, 521.664 rpm untuk pemakaian satu bulan ; 517.44 rpm, 517.792 rpm, 520.96 rpm untuk pemakaian dua bulan; 511.808 rpm, 512.16 rpm, 513.92 rpm untuk tiga bulan.   PT. Timah (Persero) Tbk. is the largest tin mining company in the world which uses suction ships of Bucket Wheel Dredger as one of the offshore mining methods. Water is used as a carrier medium to distribute mining materials from seafloor to the filtration unit by pumps through piping networks. During the dredging process, it is found there is still tin metal material left on the ocean floor. This causes dredging process is less optimal. Based on the condition, it needed an analysis to find optimum operating process for each excavation depth. In this research, theoretical head calculations were carried out where the procedure began with supporting data collection, then calculated it to get results. In field conditions, changes in pipe cross section were obtained due to erosion. The Bernoulli equation was used to calculate head, Darcy-Weisbach equation was used for the loss of major and minor head where the flow capacity was fixed at 7747.2 m3/h with digging angle variations of 30 °, 35 °, and 40 ° in the cross-sectional area for new, 1 month, 2 months and 3 months usage. The optimum operating point of the slurry pump for each angles were obtained at 517.08 rpm, 517.44 rpm, 520.96 rpm for new usage; 517.44 rpm, 517.44 rpm, 521,664 rpm for one month usage; 517.44 rpm, 517,792 rpm, 520.96 rpm for two months usage; and 511,808 rpm, 512.16 rpm, 513.92 rpm for three months usage.

scholarly journals Kajian Performansi Pompa Slurry pada Cutter Suction Dredger dengan Variasi Sudut Gali 35°, 40° dan 45°

2018 ◽  
Vol 1 (1) ◽  
pp. 028-033
Author(s):  
Asybel Bonar ◽  
Tekad Sitepu
Keyword(s):  
Cross Sectional Area ◽  
Piping System ◽  
Sectional Area ◽  
Cross Sectional ◽  
Carrier Medium ◽  
Flow Capacity ◽  
Piping Networks ◽  
Filtration Unit ◽  
Offshore Mining

Cutter Suction Dredger adalah salah satu metode penambangan lepas pantai. Untuk mendistribuskan material tambang dari dasar laut menuju unit penyaringan, digunakan air sebagai media pembawa dibantu dengan pompa melalui jaringan pemipaan. Sistem pemipaan merupakan bagian yang sangat penting dalam menyalurkan fluida. Dalam pengoperasiannya didapat kerugian yang menimbulkan beban tambahan yang ditimbulkan oleh gesekan antara fluida dan padatan denga pipa beserta dengan komponennya.Dalam penelitian ini, peneliti melakukan perhitungan head secara teoritis dimana prosedur dimulai dengan pengumpulan data data pendukung, kemudian melakukan perhitungan untuk mendapatkan hasil. Dalam kondisi lapangan, didapat terdapat perubahan luas penampang pipa dikarenakan oleh gesekan . Untuk menghitung head, digunakan persamaan Bernoulli, untuk kerugian head major dan head minor digunakan persamaan Darcy-Weisbach dimana kapasitas aliran adalah tetap sebesar 250 m3/h solid insitu dengan variasi sudut gali 25°,35°, dan 45° pada luas penampang dengan pemakaian baru, 1 bulan, 2 bulan, dan 3 bulan. Didapat besar head untuk setiap sudut secara berurutan adalah 399 rpm, 414.762 rpm, dan 433.984 rpm untuk pemakaian baru, 398.808 rpm, 413.987 rpm, 432.713 rpm untuk pemakaian 1 bulan, 397.368 rpm, 412.888 rpm, 428.125 rpm untuk pemakaian 2 bulan, dan 395.263 rpm, 411.021 rpm, 420.069 rpm untuk pemakaian 3 bulan.   Cutter Suction Dredger is an offshore mining method. Water is used as a carrier medium to distribute mining material from the seafloor to the filtration unit, by pump through piping networks. Piping system is a very important part in channeling fluid. In the operation, the loss is obtained because of the additional burdens caused by friction between fluid and solid with pipe along with its components. In this study, researcher conducted theoretical head calculations where the procedure started by collecting supporting data, then calculated it to get results. In field conditions, it was found that there was a change in cross-sectional area of ​​the pipe due to friction. Bernoulli equation was used to calculate head, Darcy-Weisbach equation was used for loss of major head and head minor where flow capacity was fixed at 250 m3/h solid in situ with variation of digging angle were 25 °, 35 °, and 45 ° on cross-sectional area for new, 1 month, 2 months and 3 months usage. The head sizes for each angle sequentially were 399 rpm, 414,762 rpm and 433,984 rpm for new usage; 398,808 rpm, 413,987 rpm, 432,713 rpm for 1 month usage; 397,368 rpm, 412,888 rpm, 428,128 rpm, 428,125 rpm for 2 months usage; and 395,263 rpm, 411,021 rpm, 420,069 rpm for 3 months usage.

Hypertension: The future of Ghana (protocols) (Preprint)

2018 ◽  
Author(s):  
Cecilia Amponsem-Boateng ◽  
Weidong Zhang ◽  
Timothy Oppong Bonney ◽  
Godfery Opolot ◽  
QingLin Zhao
Keyword(s):  
Adult Population ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Community Based ◽  
Cross Sectional ◽  
Current Prevalence ◽  
The World ◽  
The Future ◽  
Depth Study ◽  
Youth Study

BACKGROUND Many studies on HPT (hypertension) in Ghana are focused mainly on the adult population. There is no in-depth study conducted on the youth of Ghana to ascertain what the future holds for the nation with regards to HPT. OBJECTIVE The aim of this protocol is to assess the current prevalence of HPT and pre HPT of the youth of Ghana, estimate the future prevalence and propose possible interventions. METHODS : A community-based, cross-sectional study will be conducted in selected SHS (Senior High Schools) in the Ashanti region of Ghana to assess the prevalence of HPT and pre HPT within the youth of Ghana. RESULTS Phase A data collection in progress CONCLUSIONS Discussion: Early detection efforts such as screening at risks population are embraced in the prevention of HPT as this study seeks to do, and to convey clarity of HPT and pre HPT. Though focusing on Ghanaian youth, study findings could also be used as a reference for Africa and the world at large.

HUBUNGAN ANTARA PENDIDIKAN DAN STATUS EKONOMI IBU DENGAN KEJADIAN DIARE PADA BALITA DI PUSKESMAS SEKIP PALEMBANG TAHUN 2014

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Wulan Citra Sari Wulan Citra Sari
Keyword(s):  
Economic Status ◽  
Chi Square ◽  
Cross Sectional ◽  
Diarrhea Case ◽  
The World ◽  
Diarrhea Disease ◽  
United Nation ◽  
Research Show ◽  
Improve Health ◽  
Children Under 5

  ABSTRACT Diarrhea is cause the number one of a death in the world. The united Nation Children’s Found (UNICEF) thinks about every 30 second there one a child die because diarrhea. Diarrhea disease still be a problem for society healthy in Indonesia well reviewed of morbidity and mortality ant the mark of deaths and “Kejadian Luar Biasa (KLB)” that caused. Accrodin to WHO the mark of diarrhea illness 2010 is 411 patients per 1.000 population. The digit of death diarrhea is 14% from the digit of death over all. The purpose of this research to know a connection between education and mother economic status with toodler (children under 5 years old) diarrhea case at Puskesmas Sekip Palembang in February 2014. Desaign of this research to survey analitic by do coloser Cross Sectional in Accidental Sampling tehnic which one the variable who get research, include education and mothers economic status. The sampel in this research in 33 mothers who come by bring their toodler to MTBS Puskesmas Sekip Palembang at February 2014. Each variabel who get research, then get analysis by use analysis Chi-Square by decisios X² table (3,481). The result of this research show that the respondent by diarrhea as many is 15 respondent (45,5%) and didn’t diarrhea 18 respondent (54,5%). This of high education 13 repondent (39,4%) and less education is many as 20 respondent (60,6%), the respondent based to the high economic status as many as 13 respondent (39,4%). From statistic test Chi-Square show that, there a connection between education  with diarrhea case in X² count = 4,313, and there a connection between mothers economic status with case diarrhea at X² count= 4,917. From the results of this study are expected to further improve health education, especially regarding the incidence of diarrhea in infants to mothers who have young children understand more about the incidence of diarrhea.     ABSTRAK Diare adalah penyebab nomor satu kematian di dunia. The United Nations Children’s Fund (UNICEF) memperkirakan bahwa setiap 30 detik ada anak meninggal karena diare. Penyakit diare masih merupakan masalah kesehatan masyarakat di Indonesia baik ditinjau dari angka kesakitan dan angka kematian serta kejadian luar biasa (KLB) yang ditimbulkan. MenurutWHO angka kesakitan diare pada tahun 2010 yaitu 411 penderita per 1000 penduduk. Angka kematian diare 14% dari angka kematian balita secara keseluruhan. Tujuan penelitian ini untuk mengetahui hubungan antara pendidikan dan status ekonomi ibu dengan kejadian diare pada balita di Puskesmas SekipPalembang pada bulan Februari Tahun 2014. Desain penelitian ini adalah survey analitik dengan pendekatan Cross Sectional dalam teknik Accidental Sampling dimana variableyang diteliti meliputi pendidikan dan status ekonomi ibu. Sampel pada penelitian ini adalah 33ibu yang datang membawa anak balitanya berobat ke MTBS puskesmas Sekip Palembang pada bulan FebruariTahun 2014. Masing-masing variabel yang diteliti kemudian dianalisa dengan menggunakan analisis Chi-Square dengan ketetapan X² Tabel (3,481). Hasil penelitian ini menunjukan bahwa responden dengan diare sebanyak 15 responden (45,5%) dan tidak diare 18 responden (54,5%), responden berdasarkan pendidikan tinggisebanyak 13responden (39,4%) dan pendidikan rendah sebanyak 20 responden (60,6%), responden berdasarkan status ekonomi tinggi sebanyak 20 responden (60,6%) dan yang status ekonomi rendah sebanyak 13 responden (39,4%). Dari uji statistik Chi-Square menunjukkan ada hubungan antara pendidikan dengan kejadian diare pada X²hitung= 4,313, dan ada hubungan antara status ekonomi ibu dengan kejadian diare pada X²hitung= 4,917. Dari hasil penelitian ini diharapkan agar lebih meningkatkan penyuluhan kesehatan khususnya tentang kejadian diare pada balita agar ibu yang mempunyai balita lebih memahami tentang kejadian diare.  

Studies of microbial acclimation to hard chemicals on the basis of respiratory quinone profiles and kinetic analyses

1996 ◽  
Vol 34 (5-6) ◽  
pp. 249-256 ◽  
Author(s):  
Hong-Ying Hu ◽  
Mamie Nozawa ◽  
Koichi Fujie ◽  
Tsuyoshi Makabe ◽  
Kohei Urano
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Population Dynamics ◽  
Volatile Substance ◽  
Operating Conditions ◽  
Biological Wastewater Treatment ◽  
Basic Information ◽  
Optimal Operating ◽  
Respiratory Quinone ◽  
Treatment Processes ◽  
Quinone Profile

The population dynamics of microbes in the biological wastewater treatment processes such as a submerged biofilter was investigated to obtain basic information to determine the optimal operating conditions. The effects of coexistence of biodegradable substances such as glucose and peptone on the acclimation of microbes in the biofilm to hard chemicals such as acrylonitrile (AN), which is poorly biodegradable and a volatile substance, was investigated on the basis of the respiratory quinone profile. Kinetic study of the removal of AN in the course of acclimation of microbes was investigated using a laboratory-scale submerged biofilter as well. It was ascertained that the acclimation of the microbes to AN was accelerated by coexistence of biodegradable substances, and the microbial phase after acclimation differed from those with the coexistence of glucose and peptone. The quinone profiles in the acclimation showed that Brevibacterium sp. and Pseudomonas aeruginosa, of which the predominant quinone of the respiratory chain is menaquinone-8(H2) and ubiquinone-9, respectively, multiplied selectively in the acclimation course without and with the coexistence of glucose and peptone, respectively. It was also made clear that there were few kinds and number of protozoa and metazoa in the biofilter treating the wastewater containing AN.

Validation of mathematical model of electrothermal calculation of DC catenary on the basis of scale model

2018 ◽  
Vol 77 (4) ◽  
pp. 222-229 ◽  
Author(s):  
A. V. Paranin ◽  
A. B. Batrashov
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Scale Model ◽  
Contact Network ◽  
Scaled Model ◽  
Cross Sectional ◽  
Current Collection ◽  
Topological Features ◽  
Study Results ◽  
Real Physical Process

The article compares the results of calculation of the finite element simulation of current and temperature distribution in the scale model of the DC catenary with the data of laboratory tests. Researches were carried on various versions of the structural design of catenary model, reflecting the topological features of the wire connection, characteristic of the DC contact network. The proportions of the cross-sectional area of the scaled model wires are comparable to each other with the corresponding values for real DC catenary. The article deals with the operating conditions of the catenary model in the modes of transit and current collection. When studying the operation of the scale catenary model in the transit mode, the effect of the structural elements on the current distribution and heating of the wires was obtained. Within the framework of the scale model, theoretical assumptions about the current overload of the supporting cable near the middle anchoring have been confirmed. In the current collection mode, the experimental dependences of the current in the transverse wires of the scale model are obtained from the coordinate of the current collection point. Using the model it was experimentally confirmed that in the section of the contact wire with local wear, not only the temperature rise occurs but also the current redistribution due to the smaller cross section. Thus, the current share in other longitudinal wires of the scale model increases and their temperature rises. Scale and mathematical models are constructed with allowance for laboratory clamps and supporting elements that participate in the removal of heat from the investigated wires. Obtained study results of the scale model allow to draw a conclusion about the adequacy of the mathematical model and its correspondence to the real physical process. These conclusions indicate the possibility of applying mathematical model for calculating real catenary, taking into account the uneven contact wear wire and the armature of the contact network.

scholarly journals Psychological impact in the time of COVID-19: A cross-sectional population survey study during confinement

2021 ◽  
pp. 135910532098558
Author(s):  
Carmina Castellano-Tejedor ◽  
María Torres-Serrano ◽  
Andrés Cencerrado
Keyword(s):  
Chronic Conditions ◽  
Population Survey ◽  
Psychological Impact ◽  
Survey Study ◽  
Psychological Interventions ◽  
Community Based ◽  
Cross Sectional ◽  
Young Females ◽  
The World ◽  
The Impact

The transformation that COVID-19 has brought upon the world is unparalleled. The impact on mental health is equally unprecedented and yet unexplored in depth. An online-based survey was administered to 413 community-based adults during COVID-19 confinement to explore psychological impact and identify high risk profiles. Young females concerned about the future, expressing high COVID-related distress, already following psychological therapy and suffering from pre-existing chronic conditions, were those at highest risk of psychological impact due to the COVID-19 situation. Findings could be employed to design tailored psychological interventions in the early stages of the outbreak to avoid the onset/exacerbation of psychopathology.

scholarly journals Evaporator Optimization of Refrigerator Systems Using Quality Analysis

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 555
Author(s):  
Sangkyung Na ◽  
Sanghun Song ◽  
Seunghyuk Lee ◽  
Jehwan Lee ◽  
Hyun Kim ◽  
...  
Keyword(s):  
Power Consumption ◽  
Operating Time ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Quality Analysis ◽  
Lubricating Oil ◽  
Optimal Operating ◽  
Compressor Piston ◽  
Refrigerator Temperature ◽  
Visualization Experiments

In this study, evaporator optimization, via both experimental and simulation methods was conducted. To evaluate the evaporator performance, under the optimal system, the compressor operating time and the effects of oil on the refrigerator system were studied. If the temperature of the refrigerator chamber reaches the setting value, the compressor stops working and it leads to the temperature of the refrigerator chamber slowly increasing, due to the heat transfer to the ambient. When the refrigerator temperature is out of the setting range, the compressor works again, and the refrigerator repeats this process until the end of its life. These on/off period can be controlled through the compressor piston movement. To determine the optimal compressor operating conditions, experiments of monthly power consumption were conducted under various compressor working times and the lowest power consumption conditions was determined when the compressor worked continuously. Lubricating oil, the refrigerator system, using oil, also influenced the system performance. To evaluate the effect of oil, oil eliminated and oil systems were compared based on cooling capacity and power consumption. The cooling capacity of the oil eliminated system was 2.6% higher and the power consumption was 3.6% lower than that of the oil system. After determining the optimal operating conditions of the refrigerator system, visualization experiments and simulations were conducted to decide the optimal evaporator and the conventional evaporator size can be reduced by approximately 2.9%.

scholarly journals The impact of the COVID-19 pandemic on socio-economic and sustainability

2021 ◽  
Author(s):  
Xueli Wei ◽  
Lijing Li ◽  
Fan Zhang
Keyword(s):  
World Economy ◽  
Social Economy ◽  
Secondary Data ◽  
Well Being ◽  
Cross Sectional ◽  
The Social ◽  
The World ◽  
The Status ◽  
Sectional Analysis ◽  
The Impact

Pumping elephantThe COVID-19 pandemic has adversely affected the lives of people around the world in millions of ways . Due to this severe epidemic, all countries in the world have been affected by all aspects, mainly economic. It is widely discussed that the COVID-19 outbreak has affected the world economy. When considering this dimension, this study aims to examine the impact of the COVID-19 pandemic on the world economy, socio-economics, and sustainability. In addition, the research focuses on multiple aspects of social well-being during the pandemic, such as employment, poverty, the status of women, food security, and global trade. To this end, the study used time series and cross-sectional analysis of the data. The second-hand data used in this study comes from the websites of major international organizations. From the analysis of secondary data, the conclusion of this article is that the impact of the pandemic is huge. The main finding of the thesis is that the social economy is affected by the pandemic, causing huge losses in terms of economic well-being and social capital.

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