Miracle-dz/UniFAR-FTUs huggingface dataset:
Selective dispersion-flocculation and flotation studies on a siliceous copper ore

A low-grade copper ore from Mpanda Mineral Field (MMF), Tanzania containing 0.90% Cu, 10.40% Fe and 58.3% SiO2 was subjected to beneficiation adopting selective dispersion, flocculation and flotation techniques. Based on the mineralogical characterization of the sample chalcopyrite, pyrite and quartz were identified as the major minerals. The isoelectric point of MMF ore was observed to be at pH 2.7, signifying that the ore was highly siliceous. The addition of sodium trisilicate and xanthan gum shifted the zeta potential of ore to more electronegative values. Adsorption of xanthan gum on chalcopyrite and silica indicated that the maximum adsorption was at pH 2.3 for chalcopyrite and the adsorption isotherm exhibited L2 type of the Giles classification. On the contrary, no adsorption of xanthan gum on silica was observed. The ground ore was selectively dispersed and flocculated at pH 9.7 using 30 ppm of sodium trisilicate and 30 ppm of xanthan gum. The grade of CuFeS2 was improved to 19.8% after 3 desliming stages. Flotation of the flocculated portion was carried out at pH 10.30 using 30 g/t of potassium amyl xanthate and potassium ethyl xanthate (1:1) , 40 g/t of Na2S as a sulphidising agent and methyl iso-butyl carbinol (MIBC) as a frother yielding a rougher concentrate with silica and chalcopyrite grades of 8.4% and 23.5% respectively with corresponding recoveries of 4.8% and 92.8% respectively. Additionally, rougher concentrate was subjected to cleaner flotation yielding silica and chalcopyrite grades of 1.8% and 29.2 % respectively and with recoveries of 1.2% and 89.1% respectively.
Slag–Copper Equilibria of Selected Trace Elements in Black Copper Smelting. Part I. Properties of the Slag and Chromium Solubility

ABSTRACT The solubility of chromium in alumina- and lime-containing (≈5 wt% Al2O3 and 0- ≈ 10 wt% CaO) iron silicate slags has been measured at 1,300°C. In order to avoid contamination and the effects of further elements in the slag, the measurements were carried out at silica saturation. The solubility of chromium was a function of oxygen partial pressure. At high oxygen partial pressures PO2 ≈ 10−5 atm, the solubility was about 0.15 wt% (Cr) and it increased to about 0.3 wt% (Cr) in reducing conditions of pO2 ≈ 10−10 atm. Alumina and lime seemed to increase the solubility slightly.
Modelling technical efficiency and technology gap in smallholder maize sector in Ethiopia: accounting for farm heterogeneity

ABSTRACT This paper examines the effect of farm heterogeneity on the technical efficiency and technology gap of maize production in Ethiopia. We utilize comprehensive household-level data in 2010, 2013 and 2015 for three major maize producing regions in Ethiopia. We estimate technical efficiency using a bias-corrected stochastic meta-frontier model that accounts for technological differences and the consistent ‘true’ fixed-effects stochastic frontier model, which disentangles unobservable farm heterogeneity from inefficiency. We find that maize farmers produce below their potential output with the technology available and the prevailing environmental conditions in their regions. The results show that Oromia has the highest technical efficiency, followed by SNNP, and Benishangul-Gumuz is the least efficient in maize production. These findings generate important policy implications for achieving increased technical efficiency and reduce the technology gap in maize production. Moreover, the level of education, age of household head, family size, household wealth, and off-farm employment and extension services significantly affect technical efficiency in maize production in Ethiopia.
Unraveling Dynamics of Entangled Polymers in Strong Extensional Flows

The traditional Doi–Edwards tube model, applied to extensional flows at strain rates above the inverse Rouse time, predicts that the tube deforms affinely, which implies that the extensional stress reaches its plateau as soon as the chain has become locally fully stretched, even if the chain is still folded, and far from being completely unraveled. By starting from a state in which the chain is in a locally fully stretched, but folded, state, we develop an “entangled kink dynamics algorithm” that predicts the final unraveling of an ensemble of mutually entangled, folded chains, driven by a combination of drag forces and chain tension, with negligible Brownian motion. Equations for motions of both entangled folds and unentangled folds in which two chains hook together at a single fold point are derived and solved, including the effects of constraint release that occurs when the end of one chain passes through the fold at which that chain is entangled. This model predicts that the stress approaches its fina.
Pyrolysis and combustion kinetics of disposable surgical face mask produced during Covid-19 pandemic

ABSTRACT In order to prevent the spread of Covid 19, most countries have made face masks compulsory. Millions of face masks are disposed of daily in the community. Therefore, the aim of the present research work is to carry out the pyrolysis and combustion process of the face mask in a thermogravimetric machine. The kinetic parameter activation energy was calculated using model-free methods (Flynn-Wall-Ozawa, Kissinger-Akihara-Sunose, and Starink) at four different heating rates (5, 10, 15, and 20°C/min). Results have shown that face masks decompose in the temperature range of 320–480°C during pyrolysis with a maximum derivative weight loss of 2.5%/°C. Combustion took place between 200°C and 370°C with a maximum derivative weight loss of 1.25%/°C. The residue char at 500°C for pyrolysis and combustion was in the range of 1.74 to 2.73 wt. %. The average activation energies calculated using model-free methods for pyrolysis and combustion were ~135 kJ/mol and ~65 kJ/mol, respectively. In conclusion, combustion process could be the immediate solution to dispose of the face mask due to lower activation energy and decomposition temperature and low emissions as compared to pyrolysis process.
Timing and synchronisation for high-loss free-space quantum communication with Hybrid de Bruijn Codes

Satellite-based long distance free space quantum key distribution has the potential to realize global quantum secure communication networks. Detecting faint quantum optical pulses sent from space requires highly accurate and robust classical timing systems to pick out signals from the noise and allow for reconciliation of sent and received key bits. For such high loss applications, we propose a fault-tolerant synchronisation signal coding and decoding scheme based on de Bruijn sequences. A representative synchronisation timing system was tested in laboratory conditions and demonstrated high fault tolerance for the error correction algorithm even under high loss. We also discuss performance limitations of this solution, analyse the maximum error-tolerance of the scheme and the estimated computational overhead, allowing for the possibility of implementation on a real-time system-on-chip. This solution not only can be used for synchronisation of high-loss channels such as between satellites and ground stations, but can also be extended to applications with low loss, high bit error rate, but requiring reliable synchronisation such as quantum and non-quantum communications over terrestrial free space or fibre optic channels.
The Late Quaternary Hydrological Changes in the Eastern Tarim Basin Inferred From 10Be Exposure Ages of River Terraces

Reliable information on the dynamics of hydrological changes is crucial for the social and economic stabilities and sustaining developments in arid Central Asia. However, the few long‐term hydrological records limit understanding of the relationship between meltwater runoff and climate changes, because the short‐term observations show a paradoxical runoff trend with climate warming across Central Asia. Here, we made a systematic analysis on the 10Be exposure ages of the river terraces developed in the eastern Tarim Basin and reconstructed the hydrological regime changes during the past 170 ka. These data, together with the ages of the river terraces in the water source areas, suggest that the exposure ages of river terraces in the eastern Tarim Basin reflect the depositional time of alluvial sediments. The meltwater runoff displays an inverse relation with the North Hemisphere Summer Insolation and temperature changes on both orbital and millennial time scale, indicating that low temperatures favor high runoff fluxes. The observed correlation between the hydrological regimes and temperature changes suggests that the runoff will decrease and thus climate will become drying with global warming in arid Central Asia.
Hydrothermal Vents Are a Source of Old Refractory Organic Carbon to the Deep Ocean

Based on the C‐14 data of Druffel et al. (2021, https://doi.org/10.1029/2021gl092904) along the Eastern Pacific Rise, dissolved organic carbon (DOC) in the deep ocean is old and thus refractory. Their data in combination with previous He‐3 data indicate that the source of this aged DOC is from the hot waters emanating from hydrothermal vents along the ridge axis. The isotopic and structural composition of the source DOC is unknown, which requires a concerted effort by the marine organic chemistry community to elucidate these chemical forms.
Low Contribution of the Fast‐Sinking Particle Fraction to Total Plankton Metabolism in a Temperate Shelf Sea

Temperate shelf seas are productive areas with the potential to export high quantities of particulate organic carbon (POC), as sinking particles, to the sediments or off‐shelf to the open ocean. The amount of carbon which can be exported depends partly on the amount of POC produced and on the remineralization processes occurring on the sinking material. Here, we assessed the relative seasonal importance of microbial respiration and bacterial production associated with suspended, slow‐ and fast‐sinking particle fractions. The three fractions were collected in the Celtic Sea above and below the seasonal thermocline in November 2014, April and July 2015 using Marine Snow Catchers. The slow‐sinking fraction had higher microbial respiration and bacterial production rates than the fast‐sinking fractions, and these two fractions sustained rates of microbial respiration and bacterial production between 1 and 3 orders of magnitude lower than the suspended fraction. This low contribution of the slow‐ and fast‐sinking fractions was consistent with their low contribution to the POC concentration at the two depths sampled. The POC‐specific respiration rates associated with the slow‐ and fast‐sinking fractions were low (median 0.17 and 0.08 d−1, respectively), indicating low‐sinking particle degradation. Our results indicate that ∼5% of the POC in surface waters can be exported below the thermocline.
The Effect Of Problem-Based Learning Model During Pandemic On The Thematic Learning Outcomes Of Students In Elementary School

This study aims to determine the effect of the Problem Based Learning learning model during the pandemic on the thematic learning outcomes of students in grade IV Private Primary School HKBP Tomuan with Science Subjects on theme 6 My ideals, sub-theme 1 I and my ideals, learning 2. Types This research is Classroom Action Research using 2 cycles with four stages, namely planning, action, observation, and reflection. The subjects of this study were the fourth-grade students of HKBP Tomuan Private Elementary School, totaling 20 people, while the object of this research was the thematic learning outcomes of students by applying problem-based learning models. The technique of collecting data is by observing and conducting a pretest at the beginning of learning and a posttest at the end of learning. Based on the analysis of the data obtained in the first cycle by not using the problem-based model, the learning outcomes of 12 students reached the KKM, namely 60 to 75%, and 8 students did not reach the KKM, which was
Determining the Differences in the Impacts of Factors Affecting Sovereign Credit Rating: A Case Study of Developing ASEAN and Developed Countries

The paper uses the ordered logit regression model on table data to determine the differences in the impact of factors affecting the sovereign credit ratings of ASEAN developing countries compared to other developed countries. The results show that the impact of the macroeconomic indicators on the sovereign credit ratings in ASEAN developing countries decreases in comparison to the impact of factors in developed countries. Besides on that, there is no difference in the impact of the factors demonstrates the efficiency of governance on sovereign credit ratings in developing ASEAN countries compared to developed countries.
Cyclodextrin-based gefitinib nanobubbles for synergistic apoptosis in lung cancer

Abstract The present research work aimed to develop and characterize nanobubbles (NBs) for synergistic action in human cell line A549 using gefitinib and oxygen. NBs were prepared by loading oxygen in β-cyclodextrin-based inclusion complex (IC), whereas in nanosponges by polymer condensation method. Initially, the amino-functionalization was performed using (3-aminopropyl) triethoxysilane and then, underwent PEGylation to achieve site-specific action. The loading capacities of PEGylated and non-PEGylated NBs of gefitinib were found to be 85.11 ± 2.31% and 86.14±1.24%, respectively, whereas oxygen levels were found to be 2.8mg/L and 6.9mg/L, respectively. The synergistic effect of gefitinib NBs was observed by flow cytometry due to apoptosis of cell line A549 (with apoptotic rate ranged from 35.2±2.15% to 73.6±1.57%) by inhibiting EGFR pathway and further confirmed using western blotting technique. Dual delivery of gefitinib and oxygen from β-cyclodextrin-based nanosponges showed that NBs act as a novel therapy in the treatment of non-small cell lung cancer. Graphical Abstract
Presentation and Evaluation of the IPSL‐CM6A‐LR Ensemble of Extended Historical Simulations

The Institut Pierre‐Simon Laplace Climate Modeling Center has produced an ensemble of extended historical simulations using the IPSL‐CM6A‐LR climate model. This ensemble (referred to as IPSL‐EHS) is composed of 32 members over the 1850–2059 period that share the same external forcings but differ in their initial conditions. In this study, we assess the simulated decadal to multidecadal climate variability in the IPSL‐EHS. In particular, we examine the global temperature evolution and recent warming trends, and their consistency with ocean heat content and sea ice cover. The model exhibits a large low‐frequency internal climate variability. In particular, a quasi‐bicentennial mode of internal climate variability is present in the model and is associated with the Atlantic Meridional Overturning Circulation. Such variability modulates the global mean surface air temperature changes over the historical period by about ∼ 0.1K. This modulation is found to be linked to the phase present in the initial condition state of each member. This variability appears to decrease during the 1850–2018 period in response to external forcings. The analysis of the ocean heat content reveals furthermore an overestimation of the ocean stratification, which likely leads to an overestimation of the recent warming rate on average.
Recent developments on XRF spectra evaluation

Abstract Since the advent of X-Ray fluorescence (XRF) spectrum analysis technology, with its wide range of elemental analysis, rapid, nondestructive analysis characteristics, and better detection accuracy, the workload of semi-quantitative analysis has taken half of the total analysis in contemporary research institutes and university laboratories engaged in material research. In addition, XRF has been widely and efficiently used in analytical chemistry, geological and mineral survey, ecological and environmental monitoring, food and drug detection, archeology and other fields. XRF spectrum processing technology is based on the application of mathematical principles, using reasonable algorithms to optimize the processing of spectrum data to contribute more accurate quantitative analysis of key elements. Over the years, XRF spectrum processing technology has formed a relatively complete set of processes, in each step of spectrum processing, plenty of research work and paper reports have been implemented and developed. This paper mainly reviews the representative algorithms and their progress in spectrum smoothing, background subtraction and overlapping peak decomposition of XRF spectrum analysis technology, analyzes their applications in related fields, summarizes and proposes the development direction of some potential algorithms.
Effects of palliative radiotherapy and bisphosphonate usage on bone turnover marker levels in cancer patients with osteolytic bone metastases

Objectives In this study, we aimed to investigate the bone turnover marker levels according to bisphosphonate usage and radiotherapy (RT) in cancer patients with metastases in osteolytic pattern. Patients and methods A total of 52 patients (13 males, 39 females; median age: 52 years; range, 37 to 78 years) treated with RT for osteolytic bone metastases between April 2005 and April 2006 were retrospectively analyzed. Bone-specific alkaline phosphatase (BAP), amino-terminal cross-linked telopeptide of type I collagen (NTX-I), amino-terminal propeptide of type I procollagen (PINP), osteocalcin (OC), deoxypyridinoline (DPD), pyridinoline (PYD), alkaline phosphatase (ALP), creatinine, calcium (Ca), phosphate (P), magnesium (Mg), and 24-h urine Ca levels were measured in blood and urine before the initiation of RT, six weeks and six months after RT. Results A decrease in BAP, PINP, and creatinine levels was observed after RT (Week 6 p=0.006, Month 6 p=0.008). Sixteen patients who already used bisphosphonate before RT were excluded from statistical calculation. The remaining 36 patients who were treated with bisphosphonate after the first blood test were evaluated separately. In this group of patients, BAP, PINP, NTX, creatinine, and Ca levels significantly increased at six weeks after RT. The PINP and creatinine values significantly decreased at six months after RT. The variation between two different RT arms was assessed with repeated measures variance analysis. There was a statistically significant difference for NTX, OC, and creatinine levels between the first and second measurements. Conclusion Radiotherapy is an effective method in the treatment of osteolytic bone metastases. Bone turnover markers can provide an objective evaluation on RT response and parallel to imaging modalities criteria for evaluation. Bisphosphonates may alter the levels of these indicators. However, in this study, there were no statistically significant differences between the levels of markers for two different RT schedules.
Mining for silver: the role of micro-firm adaptive strategizing capabilities in harnessing senior tourism

ABSTRACT This research explores senior tourism adaptive strategizing capabilities through the lens of micro-firm owner managers. The findings derived from 24 qualitative tourism practitioner interviews demonstrated that senior tourism engagement does not necessitate a profound strategic change of direction or extensive resource reconfiguration. However, the strategic commercialization of this cohort remains under-utilized and findings perpetuated stereotypical assumptions regarding a lack of diversity within the senior market. Owner managers that actively embrace adaptive decision-making capabilities proactively target this market, whereas those with little strategic intent view senior tourism as a generic cohort of questionable commercial value. A thematic map positions the owner manager as a pivotal decision-maker within this strategic milieu and charts the trajectory of market alignment and resource transformation as a means of accessing the silver economy. Its adaptive ethos offers avenues for growth by creating bespoke authentic experiences, geared explicitly towards senior tourists as a heterogeneous cohort.
Organic carbon mineralization of the biochar and organic compost of poultry litter in an Argisol

The dynamics of the organic residues added to the soil are closely related to its mineralization rate. Therefore, the present study aimed to evaluate the organic carbon mineralization in soil samples incubated with different doses of biochar and organic compost from poultry litter. Carbon mineralization was evaluated experimentally by measuring the C-CO2 liberated by incubating 200 g of soil mixed with different doses 0, 5, 10, 15, and 20 t ha-1 of both biochar and organic compost for 61 days. The soil microbial activity, and consequently the carbon mineralization, increased with the application of doses of biochar and organic compost from the poultry litter. The highest C-CO2 mineralization was observed in the treatments that received organic compost. The carbon mineralization process followed chemical kinetics with two simultaneous reactions. The greatest amount of released and accumulated C-CO2 was observed in the soil incubated with 15 and 20 t ha-1 of organic compost from the poultry litter. The doses of biochar did not influence the content of mineralized carbon; this behavior was not verified with the use of this compost, whose highest content corresponded to 85.69 mg kg-1, applying 20 t ha-1.
Phytoremediation of Contaminated Water by Cadmium (Cd) Using Two Cyanobacteria Species (Anabaena Variabilis and Nostoc Muscorum)

Background: Water pollution with heavy metals is a severe dilemma that worries the whole world related to its risk to nature ecosystem and human being health. The main objective is to evaluate the removal efficiency of Cd with various concentrations from contaminated aqueous solution by two Cyanobacteria species (Nostoc muscorum and Anabaena variabilis). For this purpose, a designed laboratory pilot scale was applied using two cyanobacteria species (Nostoc muscorum and Anabaena variabilis), four different initial concentrations (0, 0.5, 1.0 and 2.0 mg L−1) for 21 days. Results: N. muscorum was more efficient than A. variabilis for removing Cd (II), because the optimum value of residual Cd achieved by N. muscorum after 21 days at (0.5 mg L-1) was (0.033 mg L-1), where the removal efficiency was 93.4%, while the residual Cd (II) by A. variabilis under the same conditions was (0.054 mg L-1), and the achieved removal efficiency was 89.13%. Algal growth parameters and Photosynthetic pigments were estimated for both Cyanobacteria species through the incubation period. Conclusions: High Cd concentration had a more toxic impact on algal growth. The outcomes of this study will help to produce treated water that could be reused in agrarian activities.
New Insights Into Error Decomposition for Precipitation Products

It is very important to quantify errors of precipitation estimation products. However, the existing methods do not describe all error components and are therefore not comprehensive enough. In this study, we propose a four‐component error decomposition method (4CED) that decomposes the total errors of precipitation products into four independent parts: hit positive bias, hit negative bias, false bias, and missed bias. And we use it to evaluate the performance of the three latest satellite precipitation products in the eastern monsoon region of China. Our study reveals 4CED has apparent improvements compared with the previous method. Results also provide new insights for tracking error sources and quantifying the error magnitudes of precipitation products. Moreover, the proposed 4CED can be extended to different spatial and temporal scales. Our new method will not only contribute to product upgrades, but also provide guidance for potential applications.