scholarly journals Understanding Mineral Liberation during Crushing Using Grade-by-Size Analysis—A Case Study of the Penuota Sn-Ta Mineralization, Spain

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 164 ◽  
Author(s):  
Lorena Guldris Leon ◽  
K. Johan Hogmalm ◽  
Magnus Bengtsson

Coarse comminution test-work and modeling are powerful tools in the design and optimization of mineral processing plants and provide information on energy consumption. Additional information on mineral liberation characteristics can be used for assessing the potential of pre-concentration stages or screens in the plant design. In ores of high-value metals (e.g., Ta, W), standard techniques—such as the mineralogical quantification of grain mounts by quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) or chemical analysis by X-ray fluorescence (XRF) can be challenging, due to the low relative abundance of such valuable minerals. The cost of QEMSCAN is also a limiting factor, especially considering the large number of samples required for the optimization of coarse comminution. In this study, we present an extended analytical protocol to a well-established mechanical test of interparticle breakage to improve the assessment of coarse mineral liberation characteristics. The liberation of ore minerals is a function of the rock texture and the difference in size and mechanical properties of the valuable minerals relative to gangue minerals and they may fraction in certain grain sizes if they behave differently during comminution. By analyzing the bulk-chemistry of the different grain size fractions produced after compressional testing, and by generating element by size diagrams, it is possible to understand the liberation characteristics of an ore. We show, based on a case study performed on a tantalum ore deposit, that element distribution can be used to study the influence of mechanical parameters on mineral liberation. This information can direct further mineralogical investigation and test work.

2018 ◽  
Vol 13 (2) ◽  
pp. 107
Author(s):  
Flur Ismagilov ◽  
Vajcheslav Vavilov ◽  
Oksana Yushkova ◽  
Vladimir Bekuzin ◽  
Alexey Veselov

2019 ◽  
Vol 19 (2) ◽  
pp. 101-110
Author(s):  
Adrian Firdaus ◽  
M. Dwi Yoga Sutanto ◽  
Rajin Sihombing ◽  
M. Weldy Hermawan

Abstract Every port in Indonesia must have a Port Master Plan that contains an integrated port development plan. This study discusses one important aspect in the preparation of the Port Master Plan, namely the projected movement of goods and passengers, which can be used as a reference in determining the need for facilities at each stage of port development. The case study was conducted at a port located in a district in Maluku Province and aims to evaluate the analysis of projected demand for goods and passengers occurring at the port. The projection method used is time series and econometric projection. The projection results are then compared with the existing data in 2018. The results of this study show that the econometric projection gives adequate results in predicting loading and unloading activities as well as the number of passenger arrival and departure in 2018. This is indicated by the difference in the percentage of projection results towards the existing data, which is smaller than 10%. Whereas for loading and unloading activities, time series projections with logarithmic trends give better results than econometric projections. Keywords: port, port master plan, port development, unloading activities  Abstrak Setiap pelabuhan di Indonesia harus memiliki sebuah Rencana Induk Pelabuhan yang memuat rencana pengem-bangan pelabuhan secara terpadu. Studi ini membahas salah satu aspek penting dalam penyusunan Rencana Induk Pelabuhan, yaitu proyeksi pergerakan barang dan penumpang, yang dapat dipakai sebagai acuan dalam penentuan kebutuhan fasilitas di setiap tahap pengembangan pelabuhan. Studi kasus dilakukan pada sebuah pelabuhan yang terletak di sebuah kabupaten di Provinsi Maluku dan bertujuan untuk melakukan evaluasi ter-hadap analisis proyeksi demand barang dan penumpang yang terjadi di pelabuhan tersebut. Metode proyeksi yang dipakai adalah proyeksi deret waktu dan ekonometrik. Hasil proyeksi selanjutnya dibandingkan dengan data eksisting tahun 2018. Hasil studi ini menunjukkan bahwa proyeksi ekonometrik memberikan hasil yang cukup baik dalam memprediksi aktivitas bongkar barang serta jumlah penumpang naik dan turun di tahun 2018. Hal ini diindikasikan dengan selisih persentase hasil proyeksi terhadap data eksisting yang lebih kecil dari 10%. Sedangkan untuk aktivitas muat barang, proyeksi deret waktu dengan tren logaritmik memberikan hasil yang lebih baik daripada proyeksi ekonometrik. Kata-kata kunci: pelabuhan, rencana induk pelabuhan, pengembangan pelauhan, aktivitas bongkar barang


2021 ◽  
Vol 11 (9) ◽  
pp. 4121
Author(s):  
Hana Tomaskova ◽  
Erfan Babaee Tirkolaee

The purpose of this article was to demonstrate the difference between a pandemic plan’s textual prescription and its effective processing using graphical notation. Before creating a case study of the Business Process Model and Notation (BPMN) of the Czech Republic’s pandemic plan, we conducted a systematic review of the process approach in pandemic planning and a document analysis of relevant public documents. The authors emphasized the opacity of hundreds of pages of text records in an explanatory case study and demonstrated the effectiveness of the process approach in reengineering and improving the response to such a critical situation. A potential extension to the automation and involvement of SMART technologies or process optimization through process mining techniques is presented as a future research topic.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2557
Author(s):  
Łukasz Bartela ◽  
Paweł Gładysz ◽  
Charalampos Andreades ◽  
Staffan Qvist ◽  
Janusz Zdeb

The near and mid-term future of the existing Polish coal-fired power fleet is uncertain. The longer-term operation of unabated coal power is incompatible with climate policy and is economically challenging because of the increasing price of CO2 emission allowances in the EU. The results of the techno-economic analysis presented in this paper indicate that the retrofit of existing coal-fired units, by means of replacing coal-fired boilers with small modular reactors, may be an interesting option for the Polish energy sector. It has been shown that the retrofit can reduce the costs in relation to greenfield investments by as much as 35%. This analysis focuses on the repowering of a 460 MW supercritical coal-fired unit based on the Łagisza power plant design with high temperature small modular nuclear reactors based on the 320 MWth unit design by Kairos Power. The technical analyses did not show any major difficulties in integrating. The economic analyses show that the proposed retrofits can be economically justified, and, in this respect, they are more advantageous than greenfield investments. For the base economic scenario, the difference in NPV (Net Present Value) is more favorable for the retrofit by 556.9 M€ and the discounted payback period for this pathway is 10 years.


Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 232
Author(s):  
Juan Manuel Medina ◽  
Carolina M. Rodriguez ◽  
Maria Camila Coronado ◽  
Lina Maria Garcia

The analysis of thermal comfort in buildings, energy consumption, and occupant satisfaction is crucial to influencing the architectural design methodologies of the future. However, research in these fields in developing countries is sectorised. Most times, the standards to study and assess thermal comfort such as ASHRAE Standard 55, EN 15251, and ISO 7730 are insufficient and not appropriate for the geographical areas of application. This article presents a scoping review of published work in Colombia, as a representative case study, to highlight the state-of-the-art, research trends, gaps, and potential areas for further development. It examines the amount, origin, extent, and content of research and peer-reviewed documentation over the last decades. The findings allow new insights regarding the preferred models and the evaluation tools that have been used to date and that are recommended to use in the future. It also includes additional information regarding the most and least studied regions, cities, and climates in the country. This work could be of interest for the academic community and policymakers in the areas related to indoor and urban climate management and energy efficiency.


2021 ◽  
Vol 13 (13) ◽  
pp. 2478
Author(s):  
Tyler Stumpf ◽  
Daniel P. Bigman ◽  
Dominic J. Day

Fort Stanwix National Monument, located in Rome, NY, is a historic park with a complex use history dating back to the early Colonial period and through the urban expansion and recent economic revitalization of the City of Rome. The goal of this study was to conduct a GPR investigation over an area approximately 1 acre in size to identify buried historic features (particularly buildings) so park management can preserve these resources and develop appropriate educational programming and management plans. The GPR recorded reflection events consistent with our expectations of historic structures. Differences in size, shape, orientation, and depth suggest that these responses likely date to different time periods in the site’s history. The GPR recorded other reflection anomalies that are difficult to interpret without any additional information, which suggests that pairing high-density geophysical data with limited excavations is critical to elaborate a complex site’s intricate history.


2021 ◽  
Vol 10 (5) ◽  
pp. 1097
Author(s):  
Jeong-Ju Yoo ◽  
Hee Shin ◽  
Ju Song ◽  
Minjung Kim ◽  
Jina Yun ◽  
...  

Traditionally, the diagnostic mainstay of recurrent urinary tract infection has been urinary culture. However, the causative uropathogen of recurrent cystitis has not been well established. Urine DNA next-generation sequencing (NGS) can provide additional information on these infections. Herein, we compared urine NGS results and urine cultures in patients with acute uncomplicated cystitis (AUC) and recurrent cystitis (RC), and evaluated the difference in microbiome patterns in the NGS results. Patients who underwent urine culture and NGS due to AUC or RC were retrospectively reviewed. All urine samples were collected via a transurethral catheter and studied utilizing a type of NGS called 16S ribosomal RNA gene amplification and sequencing. The sensitivity of urine NGS was significantly higher than that of conventional urine culture (69.0% vs. 16.7%, p < 0.05). The detection rate of urine NGS was slightly lower in the RC group than in the AUC group (67.7% vs. 72.7%). Microbiome diversity was significantly higher in the RC group compared to the AUC group (p = 0.007), and the microbiome composition was significantly different between the AUC and RC groups. In the urine NGS results, Pseudomonas, Acinetobacter, and Enterobacteriaceae were found in the AUC group, and Sphingomonas, Staphylococcus, Streptococcus, and Rothia spp. were detected in the RC group. Urine NGS can significantly increase the diagnostic sensitivity compared to traditional urine culture methods, especially in RC patients. AUC and RC patients had significant differences in bacterial diversity and patterns. Therefore, recurrent cystitis might be approached from a different perspective.


Author(s):  
Peng Lu ◽  
Xiao Cong ◽  
Dongdai Zhou

Nowadays, E-learning system has been widely applied to practical teaching. It was favored by people for its characterized course arrangement and flexible learning schedule. However, the system does have some problems in the process of application such as the functions of single software are not diversified enough to satisfy the requirements in teaching completely. In order to cater more applications in the teaching process, it is necessary to integrate functions from different systems. But the difference in developing techniques and the inflexibility in design makes it difficult to implement. The major reason of these problems is the lack of fine software architecture. In this article, we build domain model and component model of E-learning system and components integration method on the basis of WebService. And we proposed an abstract framework of E-learning which could express the semantic relationship among components and realize high level reusable on the basis of informationized teaching mode. On this foundation, we form an E-learning oriented layering software architecture contain component library layer, application framework layer and application layer. Moreover, the system contains layer division multiplexing and was not built upon developing language and tools. Under the help of the software architecture, we could build characterized E-learning system flexibly like building blocks through framework selection, component assembling and replacement. In addition, we exemplify how to build concrete E-learning system on the basis of this software architecture.


Geophysics ◽  
2007 ◽  
Vol 72 (1) ◽  
pp. F25-F34 ◽  
Author(s):  
Benoit Tournerie ◽  
Michel Chouteau ◽  
Denis Marcotte

We present and test a new method to correct for the static shift affecting magnetotelluric (MT) apparent resistivity sounding curves. We use geostatistical analysis of apparent resistivity and phase data for selected periods. For each period, we first estimate and model the experimental variograms and cross variogram between phase and apparent resistivity. We then use the geostatistical model to estimate, by cokriging, the corrected apparent resistivities using the measured phases and apparent resistivities. The static shift factor is obtained as the difference between the logarithm of the corrected and measured apparent resistivities. We retain as final static shift estimates the ones for the period displaying the best correlation with the estimates at all periods. We present a 3D synthetic case study showing that the static shift is retrieved quite precisely when the static shift factors are uniformly distributed around zero. If the static shift distribution has a nonzero mean, we obtained best results when an apparent resistivity data subset can be identified a priori as unaffected by static shift and cokriging is done using only this subset. The method has been successfully tested on the synthetic COPROD-2S2 2D MT data set and on a 3D-survey data set from Las Cañadas Caldera (Tenerife, Canary Islands) severely affected by static shift.


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