122 research outputs found

    Optimization of molybdenite flotation using response surface method

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    Purpose. The paper is aimed to study the molybdenite flotation from a low-grade uranium ore containing 0.2% of Mo. Methods. Three control parameters including frother (MIBC) dosage, collector (gasoline) dosage and pH, each in five levels, were investigated. Response surface methodology (RSM) was performed for statistical design and analysis of experiments and process modeling. Four quadratic mathematical models were derived for prediction of Mo recovery and Mo grade. Findings. Analysis of variance showed that frother and collector dosage were the most significant factors affecting Mo recovery and grade. In process optimization, maximum values of Mo recovery and grade were achieved as 79.13% and 2.93%, respectively. Optimum frother concentration of 78.93 g/t, gasoline dosage of 507.70 g/t, and pH of 9.77, for Mo recovery were obtained. However, in optimization studies, a case proposed the model in which the same consumption of reagents is used. Originality. There is a recognized need for type of uranium ore which contains Molybdenite, therefore working on molybdenite removing from this ore helps to recover uranium in the next steps. This research provides a novel approach to gain the optimum recovery and grade to extract uranium so easily. Practical implications. This study showed that response surface methodology could be effectively used for flotation process modeling as well as finding an optimum condition to achieve maximum recovery and grade under minimum consumption of flotation reagents.Мета. Дослідження особливостей процесу флотації молібденіту з низькозбагаченої уранової руди, що містить 0.2% молібдену. Методика. Проаналізовано три контрольних параметра флотації – дозу спінювача (метил-ізобутил-карбінол), колекторне (газолінове) дозування і ph (кожен – у п’яти різницях рівнів). Для статистичного розрахунку, аналізу експериментів і моделювання процесу флотації застосовано метод поверхневого відклику (МПВ). Були розроблені чотири квадратичні математичні моделі для розрахункових даних отримання Мо і визначення його якості. Результати. Встановлено, що спінювач і колекторне дозування є найбільш впливовими факторами при отриманні Мо та його якості. У процесі оптимізації максимальні рівні отримання Мо та якості були, відповідно, 79.13% і 2.93%. Виявлено наступну оптимальну концентрацію для Мо: спінювач – 78.93 г/т, газолінове дозування – 507.70 г/т, pH – 9.7, що підтверджено моделюванням. Наукова новизна. Запропоновано інноваційний підхід для отримання легкого й оптимального способу відновлення і ступеня вилучення урану до високої якості. Практична значимість. Метод поверхневого відклику може ефективно застосовуватися для моделювання процесу флотації з метою визначення оптимальних умов досягнення максимальної рекуперації та якості при мінімальних витратах флотаційних реагентів.Цель. Исследование особенностей процесса флотации молибденита из низкообогащенной урановой руды, содержащей 0.2% молибдена. Методика. Проанализированы три контрольных параметра флотации – доза вспенивателя (метил-изобутил-карбинол), коллекторная (газолиновая) дозировка и pH (каждый – в пяти разностях уровней). Для статистического расчета, анализа экспериментов и моделирования процесса флотации применен метод поверхности отклика (МПО). Были разработаны четыре квадратичные математические модели для расчетных данных получения Мо и определения его качества. Результаты. Установлено, что вспениватель и коллекторная дозировка являются наиболее влияющими факторами при получении Мо и его качества. В процессе оптимизации максимальные уровни получения Мо и качества были, соответственно, 79.13% и 2.93%. Выявлена следующая оптимальная концентрация для Мо: вспениватель – 78.93 г/т, газолиновая дозировка – 507.70 г/т, pH – 9.7, что подтвержденно моделированием. Научная новизна. Предложен инновационный подход для получения легкого и оптимального способа восстановления и степени извлечения урана до высокого качества. Практическая значимость. Метод поверхностного отклика может эффективно применяться для моделирования процесса флотации с целью определения оптимальных условий достижения максимальной рекуперации и качества при минимальном расходе флотационных реагентов.The financial support of the Jaber Ibn Hayan Research Laboratories, Nuclear Science and Technology Research Institute and Mr. Hasan Sedighi helps and the university of Imam Khomeini (IKIU) is gratefully acknowledged

    Modelling a cyclic maritime inventory routing problem

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    Production of micro-mesoporous alternative carbonaceous adsorbents for high-efficiency sorption of the emerging organic micropollutants from wastewater effluent

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    A partial removal of emerging organic micropollutants (EOMs) in conventional wastewater treatment plants (WWTPs) results in their continuous release to the aquatic terrestrial systems. Subsequently, EOMs such as pharmaceutical compounds, their respective metabolites as well as hormones and herbicides need a complementary treatment, e.g. sorption. However, sorptive material supposes to follow sustainable development principles as much as possible. Thus, utilizing low-cost alternative precursors for the production of sorptive material was considered in this study. Wasted activated sludge (WAS) and wood waste were used as viable primary materials for this purpose. The main objective of the present work was to remove of EOMs from a WWTP’s effluent by an effective alternative carbon adsorbent derived from the blends of sludge and woodchips. The study consisted of three stages. In the first stage, the presence of thirty multi-class EOMs was investigated in a WWTP effluent and its vicinity in Saint Lawrence River (SLR). Subsequently, the most popular EOMs were classified, then, target compounds were selected to be exposed to adsorption process. In the second stage, an effective method to produce pore enriched activated carbon from single-step activation of sludge with the additive of wood residues was developed. The produced new adsorbent increased the surface area from 1320 m2/g to 1565 m2/g after combining sludge precursor with hardwood chips. Also, the strength of the surface acidity and yield of products were mounted after wood addition. In stage 3, the sorption of an anti-depressant, venlafaxine (VEN), from aqueous solution onto the new adsorbent derived from the mixture of sludge and hardwood residues (SS:HW) was compared with a commercial granular activated carbon (CGAC). Maximum sorption capacity of the SS:HW was measured 131.57 mg/g from Langmuir isotherm while this value was 25.57 mg/g for CGAC. Then SS:HW adsorption efficiency was successfully validated on real WWTP effluent; while CGAC failed to remove a mixture of EOMs from the real matrix. The results revealed the new micro-mesoporous sludge-based (SS:HW) adsorbent could serve as an efficient tool for polishing WWTP effluent and protecting the quality of surface water resources

    Evaluating ChatGPT as a Question Answering System: A Comprehensive Analysis and Comparison with Existing Models

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    In the current era, a multitude of language models has emerged to cater to user inquiries. Notably, the GPT-3.5 Turbo language model has gained substantial attention as the underlying technology for ChatGPT. Leveraging extensive parameters, this model adeptly responds to a wide range of questions. However, due to its reliance on internal knowledge, the accuracy of responses may not be absolute. This article scrutinizes ChatGPT as a Question Answering System (QAS), comparing its performance to other existing QASs. The primary focus is on evaluating ChatGPT's proficiency in extracting responses from provided paragraphs, a core QAS capability. Additionally, performance comparisons are made in scenarios without a surrounding passage. Multiple experiments, exploring response hallucination and considering question complexity, were conducted on ChatGPT. Evaluation employed well-known Question Answering (QA) datasets, including SQuAD, NewsQA, and PersianQuAD, across English and Persian languages. Metrics such as F-score, exact match, and accuracy were employed in the assessment. The study reveals that, while ChatGPT demonstrates competence as a generative model, it is less effective in question answering compared to task-specific models. Providing context improves its performance, and prompt engineering enhances precision, particularly for questions lacking explicit answers in provided paragraphs. ChatGPT excels at simpler factual questions compared to "how" and "why" question types. The evaluation highlights occurrences of hallucinations, where ChatGPT provides responses to questions without available answers in the provided context.Comment: 15 pages, 7 figure

    Penbactam for Helicobacter pylori eradication: A randomised comparison of quadruple and triple treatment schedules in an Iranian population

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    Background & study aims: Selection of the best drug regimens for eradication of Helicobacter pylori infection especially in patients at risk of peptic ulcer relapses and the development of complications is challenging. This study assessed and compared the efficacy of the two common PPI based triple therapies to a quadruple therapy including PPI, metronidazole, amoxicillin and a bismuth compound in Iranian population. Patients & Methods: Three hundred and thirty patients with peptic ulcer and H. pylori infection were included in the study. Patients were randomly assigned to one of the three treatment protocols all given twice daily: (a) A 14-day quadruple therapy (OMAB group) comprising omeprazole 20. mg, metronicazole 500. mg, amoxicillin 1. g, and bismuth subcitrate 240. mg; (b) A 14-day triple regimen (OCP group) comprising omeprazole 20. mg plus clarithromycine 500. mg and penbactam 750. mg and (c) A 14-day triple regimen (OCA group) comprising omeprazole 20. mg plus clarithromycine 500. mg and amoxicillin 1. g. Cure was defined as a negative urea breath test at least six weeks after treatment. Results: The per-protocol eradication rates achieved with both OCP regimen (87.0%) and OCA treatment (90.8%) were significantly higher than the OMAB treatment protocol (56.0%); however, no significant difference emerged in eradication rates between the two triple treatment schedules. No significant differences between the groups were found in most side-effects. Conclusion: Two-week quadruple therapy showed a lower eradication rate compared to common triple treatment schedules when used as first-line eradication treatment for H. pylori infection in Iranian population. © 2012 Arab Journal of Gastroenterology

    The future: Urban creativity studies

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    The field of urban creativity studies has a broad range of interests including, but not limited to, street art, graffiti, urban foraging, parkour, skateboarding and guerrilla gardening. However, as with any field, once it starts to settle, a dominant paradigm tends to emerge. This will to some degree influence what is considered the core of the field, not only in terms of objects of study, but also in terms of method and theoretical approaches.info:eu-repo/semantics/publishedVersio

    Advances in the Diagnosis of GERD Using the Esophageal pH Monitoring, Gastro-Esophageal Impedance-pH Monitoring, And Pitfalls

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    PH monitoring is not capable of detecting all types of reflux, especially when the amount of acid is very low or not at all in the refluxate. Multichannel intraluminal impedance-pH monitoring (MII-pH) is used as a new method to assess bolus transport. The types of reflexes including acid, weak acid and weak alkaline MII-pH is capable of distinguishing more reflux episodes based upon use of physical and chemical parameters of the refluxate, leads to a diagnosis of normal acid reflux from abnormal nonacidic reflux. 24-h oesophagal pH monitoring can be effectively used to assess the potential relationship between symptoms and refluxes. MII-pH is capable of distinguishing more reflux episodes based upon use of physical and chemical parameters of the refluxate, leads to a diagnosis of normal acid reflux from abnormal nonacidic reflux. It can be used to confirm gastro-oesophagal reflux episodes, where has a sensitivity and specificity for diagnosing GERD in comparison with endoscopy or pH-metry

    Physiological effects of proinsulin-connecting peptide in human subcutaneous adipose tissue

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    Recent studies suggest that proinsulin-connecting peptide (C-peptide) may exhibit characteristics of a hormone and show physiological functions in various tissues. This study was aimed to determine whether C-peptide could be involved in the regulation of lipolysis, adiponectin release, and function of mesenchymal stem cells (MSCs) in adipose tissue. Human subcutaneous adipose tissue was cultured in the presence of C-peptide. The level of lipolysis was determined by glycerol measurement in the conditioned media. Effect of C-peptide on adiponectin secretion was evaluated in differentiated adipocytes. The adipogenic and osteogenic abilities of adipose MSCs were evaluated using oil red and alizarin red staining, respectively. The tetrazolium bromide test was conducted for evaluating the effect of C-peptide on MSCs proliferation. C-peptide induced a significant decrease in basal lipolysis at concentrations of 8 and 16 nM (p < 0.05). It had no significant effects on isoproterenol-stimulated lipolysis, adiponectin secretion, and adipogenic or osteogenic differentiation of MSCs. At a concentration of 4 nM, this peptide significantly increased the proliferative capability of MSCs (p < 0.05). These results suggest that C-peptide has some physiological effects in human subcutaneous adipose tissue and contributes to the regulation of basal lipolysis and pool of MSCs

    Evaluation of Lean Distribution Systems of Electricity Production Networks with Mathematical Programming and Simulation Method in Photovoltaic Power Generations

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    Nowadays waste of energy is one of the most important problems power plants are faced with all over the world. Because of costly energy sources, notably fossil energy, renewable energy technologies are becoming more indispensable. Since no specific published record has yet been found of studying mathematical programming and simulation method applied to solar power plants and photovoltaic power generations in buildings as a lean manufacturing method, in this paper, by using mathematical programming and simulation method, we propose an approach consisting of the combination of mathematical and economic models used for distribution systems of electricity transmission networks in solar power plants installed out of the city, and photovoltaic power generations in buildings of the city.The main approach is to use the simulation method for both models and compare the results with each other. Finally, by analyzing the test results, the optimum process of solar energy is presented. This aims- above all- to lead to cost reduction by appraising the percentage of country energy demand in distribution systems of electricity transmission networks. Moreover, the paper goes on to discuss constructing new solar power plants, or using new methods and technologies to satisfy the country demand which has the minimum rate of energy waste and the maximum earned value. Besides, system costs and the rate of energy waste during the transmission are considered as two criteria for comparison, and then by the test results of the simulation, the optimum procedure of the suggested models is presented

    Gli effetti sul flusso aereo nasale della turbinoplastica inferiore in corso di rinosettoplastica

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    La rinoplastica è una procedura chirurgica molto comune e al tempo stesso di elevata complessità. Uno degli aspetti più discussi di tale chirurgia sono gli insoddisfacenti esiti funzionali dovuti spesso ad un eccessivo restringimento dell’area della valvola nasale. Alcune procedure, come la turbinoplastica inferiore, possono favorire la prevenzione di tali problematiche ostruttive. L’intento del presente studio è quello di indagare gli effetti della turbinoplastica inferiore sulla resistenza nasale e sull’ostruzione respiratoria. In 50 pazienti è stata effettuata un’analisi preoperatoria e sei mesi dopo rinoplastica con turbinoplastica inferiore mediante rinomanometria anteriore attiva. Nessuno dei pazienti ha lamentato sintomatologia ostruttiva nasale nel preoperatorio o nel corso del postoperatorio. In accordo con i dati rinomanometrici sia le resistenze inspiratorie che quelle espiratorie hanno presentato valori migliori nel postoperatorio, ma solo le resistenze espiratorie hanno presentato una significatività statistica (p = 0,034). Le differenze in termini di flusso nasale fra maschi, femmine e differenti gruppi di età non sono state significative (p > 0,05). In conclusione dai dati del nostro studio emerge che la rinosettoplastica, associate a turbinoplastica parziale non ha un impatto negativo sulla funzionalità nasale ed in particolare sul flusso aereo attraverso le cavità nasali
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