bluuebunny/crossref_metadata_2025 huggingface dataset:
BORROWING ALTERNATIVES FOR HOUSEHOLDS IN LITHUANIA: CURRENT SITUATION, TRENDS AND CHALLENGES
Authors: Taujanskaitė Kamilė , Karklytė Ieva
Published: December 2021

Purpose – to analyse the main borrowing alternatives available to Lithuanian households and the credit market as a whole, focusing on its peer-to-peer (P2P) segment, the forecast of its growth, and possible challenges.
Research methodology – the research methods applied were scientific literature analysis, statistical data analysis, comparative analysis, correlation-regression analysis, linear trend forecasting method.
Findings – the prevailing borrowing alternative for Lithuanian households still remain bank credits. Besides, borrowing from P2P market is becoming more and more popular. Although the macroeconomic environment for all the credit market segments is the same, the P2P segment is developing significantly faster. If this trend remains unchanged, the whole credit market is likely to face challenges, such as the growth of overdue loans, insolvent customers, the rising share of non-performing-loans (NPL), etc., that may affect its overall stability.
Research limitations – the empirical study relies on the country’s macroeconomic indicators that influence household borrowing. Such factors as borrower’s age, income level, marital status and others were not taken into account in this study. The forecast of the P2P segment growth of the consumer credit market and comparison with its banking segment is based on the analysis of 4 years of real monthly statistics for both segments.
Practical implications – the performed analysis and its results can be useful for the future research within the household borrowing trends, especially in Peer-to-Peer platforms, and specifically for the Central Bank, the Ministry of Finance and other institutions that regulate the credit market, as it provides information on modern borrowing trends and the challenges it might bring. Also, for P2P platforms themselves, planning and further developing their activities and adjusting lending conditions with the aim to attract higher-quality customers.
Originality/Value – household borrowing, the credit market and the P2P platforms are widely analysed by both academics and financial institutions, such as central banks. However, it is mainly limited to the analysis of statistical data and does not pay attention to possible market development issues. This study focuses on the analysis of the growth trends of the P2P market and the potential challenges that may arise thereafter.
Ascodesmis rosicola sp. nov. and Talaromyces rosarhiza sp. nov., two endophytes from Rosa roxburghii in China
Authors: Zhang Hong , Wei Tian-Peng , Mao Yu-Tao , Ma Ming-Xia , Ma Kai , Shen Ying , Zheng Mei-Juan , Jia Wei-Yu , Luo Ming-Yan , Zeng Yan , Jiang Yu-Lan , Tao Guang-Can
Published: December 2021

Rosa roxburghii Tratt., a deciduous shrub of the family Rosaceae, is usually used as food and medicinal materials and also cultivated as an ornamental. Plant endophytic fungi are a large class of microbial resources not fully researched, with great potential applications. Two strains of Ascodesmis and Talaromyces were isolated during a survey of biodiversity on endophytic fungi of R. roxburghii in China. Multigene phylogenetic analyses showed that each of the two fungi formed a distinct lineage and separated from known congeneric species and they are proposed as two novel taxa.

Ascodesmis rosicola sp. nov. usually has one or two conspicuous simple or branched ridges extending to the majority of the ascospore surface and remarkably small asci, distinguishing it from the previously-described species in the genus Ascodesmis. Talaromyces rosarhiza sp. nov., of the section Talaromyces, is closely related to T. francoae. It differs from the latter by having both monoverticillate and biverticillate conidiophores, while those of T. francoae are biverticillate. Both novel endophytes are illustrated and described.
A taxonomic treatment of Synopeas Förster (Platygastridae, Platygastrinae) from the island of New Guinea
Authors: Awad Jessica , Bremer Jonathan S. , Butterill Philip T. , Moore Matthew R. , Talamas Elijah J.
Published: December 2021

Synopeas from New Guinea is revised, including 16 new species and four previously named species. The concepts for these species were developed in conjunction with a CO1 analysis that includes 16 New Guinean species and 3 Synopeas species from other regions. The molecular analysis determined that the New Guinea fauna does not form a clade, indicating multiple migrations. The following species are described and keyed: S. amandae Awad, sp. nov.; S. anunu Awad, sp. nov.; S. butterilli Buhl; S. codex Awad, sp. nov.; S. csoszi Buhl; S. kalubia Awad, sp. nov.; S. kiki Awad, sp. nov.; S. kira Awad, sp. nov.; S. klingunculum Awad, sp. nov.; S. luli Awad, sp. nov.; S. occultum Awad, sp. nov.; S. pattiae Awad, sp. nov.; S. psychotriae Buhl; S. pterocarpi Buhl; S. pulupulu Awad, sp. nov.; S. roncavei Awad, sp. nov.; S. sanga Awad, sp. nov.; S. toto Awad, sp. nov.; S. valavala Awad, sp. nov.; S. zhangi Awad, sp. nov.Leptacis pleuralis (Buhl), comb. nov. is transferred from Synopeas. Images of 56 holotypes of Synopeas are made publicly available online.
New family-level characters for Platygastroidea
Authors: Mikó István , Raymond Monique , Talamas Elijah J.
Published: December 2021

Platygastridae (Hymenoptera) is a diverse family of parasitoid wasps for which few studies of internal morphology have been conducted. The monophyly of the group is undisputed based on recently published molecular data, but based on morphology, the family is diagnosable from other platygastroids only by a combination of character reductions. In the present study we explored the mesosoma of Platygastroidea and found two new synapomorphies for Platygastridae: an externally visible anterior mesofurcal pit, which corresponds to an invagination that connects to the anterior portion of the mesofurca, and internally, a posteriorly shifted origin of the first wing flexors. The absence of a mesofurcal bridge and the exclusively mesopectal origin of the fore wing flexors are treated as synapomorphies for Platygastridae+Janzenellidae. Phylogenetic implications and evolutionary hypotheses regarding these traits are discussed.
Psix striaticeps (Dodd) (Hymenoptera, Scelionidae): an Old World parasitoid of stink bug eggs arrives in Florida, USA
Authors: Birkmire Sarah , Penca Cory , Talamas Elijah J. , Moore Matthew R. , Hodges Amanda C.
Published: December 2021

Psix striaticeps(Dodd) is an egg-parasitoid wasp previously known only from the Old World. We report this species from twelve counties in Florida, which are the first records in the Western Hemisphere. It was collected in yellow cylinder traps and reared from the eggs of three stink bug species:Nezara viridulaL.,Chinavia marginata(Palisot de Beauvois), andPiezodorus guildinii(Westwood). A COI barcode analysis found a 100% match between the Floridian population and a specimen from South Africa. The prospects of usingPs. striaticepsas a biological control agent against exotic stink bugs are discussed.
On the Cauchy problems associated to a ZK-KP-type family equations with a transversal fractional dispersion
Authors: Paredes Jorge Morales , Soriano Méndez Félix Humberto
Published: December 2021

In this paper we examine the well-posedness and ill-posedeness of the Cauchy problems associated with a family of equations of ZK-KP-type

   \begin{document}$ \begin{cases} u_{t} = u_{xxx}-\mathscr{H}D_{x}^{\alpha}u_{yy}+uu_{x}, \cr u(0) = \psi \in Z \end{cases} $\end{document}

in anisotropic Sobolev spaces, where \begin{document}$ 1\le \alpha \le 1 $\end{document}, \begin{document}$ \mathscr{H} $\end{document} is the Hilbert transform and \begin{document}$ D_{x}^{\alpha} $\end{document} is the fractional derivative, both with respect to \begin{document}$ x $\end{document}.
Refinements of topological invariants of flows
Authors: Yokoyama Tomoo
Published: December 2021

We construct topological invariants, called abstract weak orbit spaces, of flows and homeomorphisms on topological spaces. In particular, the abstract weak orbit spaces of flows on topological spaces are refinements of Morse graphs of flows on compact metric spaces, Reeb graphs of Hamiltonian flows with finitely many singular points on surfaces, and the CW decompositions which consist of the unstable manifolds of singular points for Morse flows on closed manifolds. Though the CW decomposition of a Morse flow is finite, the intersection of the unstable manifold and the stable manifold of closed orbits need not consist of finitely many connected components. Therefore we study the finiteness. Moreover, we consider when the time-one map reconstructs the topology of the original flow. We show that the orbit space of a Hamiltonian flow with finitely many singular points on a compact surface is homeomorphic to the abstract weak orbit space of the time-one map by taking an arbitrarily small reparametrization and that the abstract weak orbit spaces of a Morse flow on a compact manifold and the time-one map are homeomorphic. In addition, we state examples whose Morse graphs are singletons but whose abstract weak orbit spaces are not singletons.
Study case about the production of masonry concrete blocks with CDW and kaolin mining waste
Authors: Bastos Felipe ,   CONSTRUCT-LABEST, Faculty of Engineering (FEUP), University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal, Cabral Adeildo , Alcântara Perboyre , Maia Lino ,   Federal institute of education, science and technology of Ceará-IFCE, Avenue 13 de Maio, Ceará, Brazil,   Faculty of Exact Sciences and Engineering, University of Madeira, Campus da Penteada, 9020-105 Funchal, Portugal
Published: December 2021

The worldwide generation of construction and demolition waste is about 30% to 35% of the total solid waste produced annually. In addition, the extraction of minerals leaves a high-grade environmental liability with tailings, such as kaolin clay, Brazil being one of the countries with the largest deposits and production of this mineral in the world. The kaolin clay extraction serves several industries such as ceramics, crockery, and paper, among others. The objective of this work is to insert these two wastes as raw material of construction elements, specifically masonry concrete blocks, thus giving an end to the residues, demonstrating their reutilization potential. Here, blocks were manufactured with replacement of natural aggregates, stone powder, and sand, by construction and demolition waste and of kaolin clay waste. The replacement percentages were up to 34% and 16%, respectively. The blocks made with pneumatic vibration compacting procedure presented strength beyond than what is established by norm, thus giving a favorable perspective of use for these residues as building elements.
Global existence and asymptotic behavior for a viscoelastic Kirchhoff equation with a logarithmic nonlinearity, distributed delay and Balakrishnan-Taylor damping terms
Authors: Choucha Abdelbaki ,   Laboratory of Operator Theory and PDEs: Foundations and Applications, Department of Mathematics, Faculty of Exact Sciences, University of El Oued, Algeria, Boulaaras Salah , Alharbi Asma ,   Department of Mathematics, Faculty of Sciences, Amar Teledji Laghouat University, Algeria,   Department of Mathematics, College of Sciences and Arts, ArRass, Qassim University, Saudi Arabia
Published: December 2021

A nonlinear viscoelastic Kirchhoff-type equation with a logarithmic nonlinearity, Balakrishnan-Taylor damping, dispersion and distributed delay terms is studied. We establish the global existence of the solutions of the problem and by the energy method we prove an explicit and general decay rate result under suitable hypothesis.
R-optimal designs for second-order Scheffé model with qualitative factors
Authors: Ling Ling ,   School of Economics and Statistics, Guangzhou University, Guangzhou 510006, China, Li Guanghui , Zhu Xiaoyuan , Zhang Chongqi ,   School of Science, Kaili University, Kaili 556011, China
Published: December 2021

Considering a mixture model with qualitative factors, the $ R $-optimal design problem is investigated when the levels of the qualitative factor interact with the mixture factors. In this paper, the conditions for $ R $-optimality of designs with mixture and qualitative factors are presented. General analytical expressions are also derived for the decision function under the $ R $-optimal designs, in order to verify that the resulting designs satisfy the general equivalence theorem. In addition, the relative efficiency of the $ R $-optimal design is discussed.
Founding Empire: James Rennell and the Eighteenth-Century Survey of British Bengal
Authors: Chatterjee Baijayanti
Published: December 2021

Cet article tente d’analyser l’impact de la transition coloniale (à savoir, le transfert du pouvoir qui eut lieu au milieu du XVIIIe siècle entre l’empire Moghol et l’administration de l’East India Company) sur les traditions cartographiques de l’Inde. Plus précisément, l’article se concentre sur les cartographies française et britannique du Bengal qui accompagnèrent la colonisation et l’expansion impérialistes du milieu du XVIIIe siècle. Plutôt que d’envisager la cartographie coloniale comme un « exercice unidirectionnel » d’autorité, cet article s’intéresse à l’interaction et à la négociation dynamiques entre les cartographies indigène et coloniale. Il analyse les efforts déployés par le Major James Rennell et les cartographes de l’East India Company en vue de l’établissement de leur autorité politique au Bengal, grâce à l’usage de la cartographie comme instrument d’expansion coloniale. Les épreuves et les tribulations qu’on connues ces cartographes constituent le sujet de cet article.
Invisible Theatre: militarized space and the staging of affective atmospheres
Authors: Lovett Leah
Published: December 2021

This paper revisits the circumstances surrounding Brazilian theatre director, Augusto Boal’s first recorded experiment with Invisible Theatre in a restaurant in Buenos Aires (1972) in light of Anderson’s (2014) theory of affective atmospheres in their capacity to mediate structures of feeling. Drawing on original archival and performance-based research, I advance a critical account of Restaurant Theatre: The Law through a narrative reimagining of the performance and key evidence concerning the law in question that fundamentally challenges Boal’s claims for the technique as a means of social liberation from forces of oppression. The alternative possibility explored here is that Invisible Theatre developed in Boal’s practice as an atmospheric reaction to militaristic forms of urban encounter and a means with which to infiltrate structural feelings of fear. This idea is traced through Boal’s encounters with state apparatus of affective control as a political prisoner and marked dissident in exile, and with the performative concept of camouflage. Freed from the overdetermining binaries of oppressor and oppressed, I suggest Invisible Theatre can open up opportunities for practitioners seeking to stage affective atmospheres to produce transformative encounters and perceptions.
Association of the human papillomavirus infection with the recurrence of sinonasal inverted papilloma: a systematic review and meta-analysis
Authors: Rha M.-S. , Kim C.-H. , Yoon J.-H. , Cho H.-J.
Published: December 2021

Background: Although the role of human papillomavirus (HPV) in sinonasal inverted papilloma (SNIP) has been investigated, the link between HPV infection and SNIP recurrence remains controversial. This meta-analysis aimed to investigate the association between HPV infection and recurrence of SNIP. Methods: The PubMed, Web of Science, Google Scholar, and Cochrane Library databases were searched (until 16 June 2021) to collect all relevant articles. The pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using the fixed effects model. In addition, subgroup analysis, assessment of publication bias, and sensitivity analyses were performed. Results: Fourteen eligible articles, including 592 patients with SNIP, were included in this study. Pooled analysis revealed that HPV-positive cases exhibited a significantly higher OR of tumour recurrence than HPV-negative counterparts). A significant association between HPV infection and tumour recurrence remained stable in subgroup analyses according to the publication year of the studies. Conclusions: Our meta-analysis demonstrates that HPV infection is significantly associated with the recurrence of SNIP, suggesting the pathological role of HPV in SNIP. These results suggest that HPV infection should be considered in the management of SNIP.
Study and apply the advanced analysis algorithm to screen the optimal enhanced oil recovery solution for oil and gas fields in Viet Nam
Authors: Hoang Long , Trinh Thang Viet , Trieu Truong Hung , Nguyen Quy Minh , Pham Ngoc Quy , Doan Hien Huy , Hoang Linh ,   Vietnam Petroleum Institute, Vietnam  Vietnam Oil and Gas Group, Vietnam  Faculty of Oil and Gas, Hanoi University of Mining and Geology, Vietnam
Published: December 2021

Applying the methods of enhanced oil recovery (EOR) for oil and gas fields has always many risks of economic and technology because EOR projects are influenced by many characteristic factors of the reservoir such as structure of reservoir, reservoir formation, geological properties, parameters of reservoir engineering, production technology to EOR application. Some EOR methods have been successfully applied in the world, but when these methods conduct in specific reservoir with different geological characteristics, tight production conditions have resulted in failures and ineffective economic, even caused dreadful aftermath to be handled in operations. Researches, evaluations and EOR applications in Vietnam are limited and only carried out on a laboratory scale. Therefore, the ability to be applied the EOR modern technology with a large scale or full field still faces many difficulties and the feasibility of projects is not high enough. The authors have been analysed all EOR projects successfully that applied many oil and gas fields in the world and then building EOR database. Based on EOR database, a study has been conducted on statistical analysis to build EOR screening criteria for reservoir parameters from past to now. The study also combined in-depth analysis algorithms such as Fuzzy, K - mean, PCA Artificial Intelligence to screen the optimal EOR method for sandstone reservoirs of Cuu Long Basin.
Use of Artificial Neural Networks in predicting rate of penetration and optimization weight on bit for several wells in Nam Rong - Doi Moi field, Vietnam
Authors: Nguyen Hung Tien , Vu Duong Hong , Nguyen Vinh The , Tram Doan Thi , Trung Pham Van ,   Faculty of Oil and Gas, Hanoi University of Mining and Geology, Vietnam  Project block 0 and 0, PVEP, Vietnam
Published: December 2021

Obtaining the maximum Rate of Penetration (ROP) by optimization of drilling parameters is the aim of every drilling engineer. This helps to save time, reduces cost and minimizes drilling problems. Since ROP depends on a lot of parameters, it is very difficult to predict it correctly. Therefore, it is necessary and important to investigate a solution for predicting ROP with high accuracy in order to determine the suitable drilling parameters. In this study, a new approach using Artificial Neural Network (ANN) has been proposed to predict ROP from real - time drilling data of several wells in Nam Rong - Doi Moi field with more than 900 datasets included important parameters such as weight on bit (WOB), weight of mud (MW), rotary speed (RPM), stand pipe pressure (SPP), flow rate (FR), torque (TQ). In the process of training the network, algorithms and the number of neurons in the hidden layer were varied to find the optimal model. The ANN model shows high accuracy when comparing to actual ROP, therefore it can be recommended as an effective and suitable method to predict ROP of other wells in research area. Besides, base on the proposed ANN model, authors carried out experiments and determine the optimal weight on bit value for the drilling interval from 1800 to 2300 m of wells in in Nam Rong Doi Moi field.
Study for gravel slection and pack operation for oil production well on Song Doc oil field
Authors: Tran Quan Anh , Nguyen An Hai , Nguyen Vinh The , Nguyen Hung Tien ,   PetroVietnam Exploration and Production Corperation, Vietnam  Faculty of Oil and Gas, Hanoi University of Mining and Geology, Vietnam
Published: December 2021

Sand control by gravel packing is by far the most reliable and effective sand control method and is being used worldwide. One of the most important factor for successful operation is gravel size selection which is suitable with properties of well and particle size of sand from the reservoir, also the operation method needs to be considered during study. Due to the variety of different oilfield, the selections of gravel size and operation method are challenges for petroleum engineer and manager. Oil production wells in Song Doc oil field are producing in Miocene and Oligocene with very high rate of sand production; some of the wells were plugged by sand. Therefore, the study on the selections of gravel size and operation method is needed and important. In this study, theory analyzing was used in order to yield advantage and disadvantage of each gravel packing method and their operation. Based on the operating condition on Song Doc field and the availability of equipment on site, gravel packing method by thru-tubing with vent screen was selected. The coil tubing was chosen as the operation method. This is the best sand control method for the Song Doc oil field with low cost and high effectiveness sand control.
Research on building the formula to determine the rate of penetration for polycrystalline diamond compact bits
Authors: Truong Tu Van , Nguyen Hung Tien , Vu Duong Hong ,   Faculty of Oil and Gas, Hanoi University of Mining and Geology, Vietnam
Published: December 2021

Nowadays, polycrystalline diamond compact (PDC) drill bits are widely used in the oil and gas industry when drilling in soft rocks. However, parameters used for the PDC bit are usually based on the instructions of the drill manufacturer with a very wide adjustment range. Therefore, it is necessary to have a specific formula in order to determine the rate of penetration parameter (ROP) for the PDC bit in evaluating the influence of the parameters, rock mechanical properties and other parameters on the rate of penetration parameter (ROP). From there, it gives reasonable parameters and improves the design of the PDC bit to improve drilling efficiency. The article applies theoretical analysis method and Dalamber's principle to illuminate and build up the impact force model for PDC bits in the rock destruction process. From the impact force model, a formula to determine ROP for PDC bits was proposed. Finally, the authors applied the research results to the actual data obtained from the Nam Rong - Doi Moi oil field. The formula for determining the rate of penetration parameter (ROP) for the PDC bit that the authors have built has high accuracy and can be applied to many different rock.
Research on solutions for connecting to marginal fields at Cuu Long basin to process and transport the products basing on existing petroleum technology and equipment
Authors: Nguyen Thinh Van ,   Faculty of Oil and Gas, Hanoi University of Mining and Geology, Hanoi, Vietnam
Published: December 2021

The Cuu Long basin is equiped with infrastructures and processing facilities serving for large-scale crude oil drilling and production operations. However, most of resevoirs in this area are now depleted, it means that they have reached their peaks and started to undergo decreasing productivity, which lead to a noticable excess capicity of equipment. In order to benefit from those declined oil fieds and maximize performance of platforms, solutions to connect marginal fields have been suggested and employed. Of which, connecting Ca Ngu Vang wellhead platform to the CPP -3 at Bach Ho oil field; platforms RC-04 and RC-DM at Nam Rong - Doi Moi oil filed to RC-1 platform at Rong oil field; wellhead platforms at Hai Su Den and Hai Su Trang oil fields to H4-TGT platform at Te Giac Trang oil field are typical examples of success. Optimistic achivements gained recently urges us to carry out this work with the aim to improve oil production of small reserves and to make best use of existing petroleum technology and equipment at the basin. Results of the research contribute an important part in the commence of producing small-scale oil deposits economically.
Optimization of control power sources and island driver system design for remotely operated vehicle (ROV)
Authors: Le Vinh Duc , Le Giap Ba , Nguyen Tuan Thanh , Hoang Dung Anh , Le Duyen Quang ,   Faculty of Oil and Gas ,Hanoi University of Mining and Geology, Hanoi, Vietnam  Joint Venture Vietsovpetro, Ba Ria – Vung Tau, Vietnam
Published: December 2021

Remotely Operated Vehicle (ROV) diving equipment system is an important device in oil and gas exploration and production, especially in the conditions of working in deep and complex waters. By design, the ROV Panther Plus 932 has no reverse steering function, limited visibility and difficult operation. To overcome that shortcoming, the authors have studied and fabricated an electronic circuit to take charge of the power reversing function on the Joystick with a function button and a Forward/Revert status indicator light. After adjusting, designing, controlling the ROV in the opposite direction, there is no need to turn the head, avoid twisting, burning cables, getting caught in obstacles or being caught up in the ROV during work, increasing cable life.
Challenges and opportunities for development of the Vietnam mineral processing in the XXI century
Authors: Pham Luan Van ,   Faculty of Mining, Hanoi University of Mining and Geology, Vietnam
Published: December 2021

Mineral mining and processing Industry of Vietnam is facing a number of huge challenges at present, but there are also great opportunities for its growth in the future. Mineral processing plants need to make breakthrough improvements in the process designing, technology and equipment utilisation in order to meet requirements of the new era. These challenges force our miners and mineral processing operators to constantly make efforts in researches and to bring best solutions to improve plant operations to ensure the requirements of safety, market demands, product quality, sustainable development and environmental friendliness. Specifically, the issues that need to be addressed urgently are capacity and quality of the workforce, tailings treatment, fine particle processing, ores of low washability, recovery rate increase and maximisation of recoverable valuable minerals, environmental issues and workplace safety monitoring and control, maximasation of production efficiency and reduction of operating costs. This report presents the current key challenges of the mining and mineral processing industry in order to help professionals and policy makers in the field of mineral mining and processing to bring rational directions for action initiate appropriate studies and improve management methods; to help mineral processing plants in improving the production efficiency and recovery of valuable minerals; to reduce operating costs and to become environmentally friendly and to develop sustainably.
Dewatering fine solid suspension by using steam pressure filtration
Authors: . Hai Thanh Pham , Peuker Urs ,   Faculty of Mining, Hanoi University of Mining and Geology, Vietnam  Institute for Mechanical Process Engineering and Mineral Processing, TU Bergakademie Freiberg, 0 Freiberg, Germany
Published: December 2021

Steam pressure filtration is the combination of mechanical and thermal in one equipment. This process shows the advantages in comparison to conventional pressure filtration by the characteristic of its distinction mechanism. Application of steam pressure filtration can be listed: dewatering the suspension of fine solid, remove the contaminant, dangerous chemical, dissolved ions, protecting the human health as well as the environment. This paper shows the mechanism of steam pressure filtration as well as the result of tests, the comparison related to the efficiency between steam pressure filtration and conventional pressure filtration. The steam pressure filtration shows the high efficiency in mechanical displacement phase in both input parameters: solid volume fraction of suspension and the height of filter cake. The residual moisture content and saturation of filter cake using steam pressure filtration are lower 10÷20% than those values of filter cake using conventional pressure filtration. Moreover, some preliminary tests taking account to the drying phase of steam pressure filtration are also showed. The moisture of fine material filter cakes is around 6÷13%. Through the result of tests, interpretation and discussion, the application of steam pressure filtration is possible in the field of mineral processing and metallurgy.
Mineralogical - geochemical characteristics of gold mineralization and its potential in the Tuong Duong area, Nghe An province
Authors: Khuong Hung The , Ha Dung Tri ,   Faculty of Geoscience and Geoengineering, Hanoi University of Mining and Geology, Vietnam  Bac Trung Bo geological division, Vietnam
Published: December 2021

Tuong Duong area, Nghe An province is considered as a high potential area of gold deposits such as the Yen Na - Yen Tinh, Ban Bon, Xieng Lip, and Na Khom gold occurrences. Based on synthesizing, geological processing data, analysis and complement of the 15 thin sections, 10 thick sections, 02 scanning electron microscope and 05 ICP - MS samples, results show that the gold mineralization has fomed from hydrothermal activities at low - moderate temperature, belonging to quartz - sulfur - gold mineral deposit type. The gold contents in orebodies vary from medium to high values, with average contents ranging from 0.8÷6.55 (g/ton). Results also provide an overview of the prospect of gold resources, serving as a basis for determining the Au prospective areas in Tuong Duong, Nghe An province. The direct calculation method for metallization parameters and Huvo methods are applied in this paper to estimate gold resources in the study area, resulting in 2.21 tons of Au - metal.
Research on treating processes of Nickel Laterite Ores in the world and Vietnam
Authors: Nguyen Khanh Tuan , Tran Toi Trung , Phung Thuat Tien ,   Southern Branch of the Vietnam Institute of Geosciences and Minerals, Vietnam  Faculty of Mining, Hanoi University of Mining and Geology, Vietnam
Published: December 2021

Laterite nickel ores, accounting for about 70% of total world nickel reserves, are very abundant and considered as an important resource of nickel. However, nickel content of laterite ores are generally low of about 0.5÷2.5% Ni. In addition, nickel minerals are very finely disseminated in the ores, so that traditional separation methods such as froth flotation, gravity method, magnetic method, and electrical separation produce very low recovery efficiency. Currently, the treatment of this type of ores is being intensively studied and directed to use common available processes including: Hydrometallurgical, pyrometallurgical, and reduction roasting - magnetic separation processes. This article aims to summarize typical studies on the characteristics of current laterite nickel ore processing technologies commonly used in the world and in Vietnam. From the review, appropriate direction for treatment of Thanh Hoa - Vietnam laterite nickel ores can be proposed.
Recovery of bauxite ore particles -1mm from tailings of the Tan Rai bauxite processing plant by mechianical classifiers
Authors: Nguyen Minh Van , Nguyen Hau Van ,   Department of Mineral processing and Metallurgy Technology, Institute of Mining Science and Technology - Vinacomin, Vietnam
Published: December 2021

Tailings of the Tan Rai bauxite mineral processing plant contain a relatively high proportion of fine bauxite ore particles of less than 1mm. This amount of discarded fine bauxite particles necessarily leads to a high loss of valuable bauxite mineral and also require more tailings dam space. Recovery of such fine bauxite ore particles may produce certain economic and environmental effects to the current processing plant. The paper presents results of the study on recovery of fine bauxite ore particles -1 mm from tailings of the Tan Rai - Lam Dong bauxite mineral processing plant by the use of mechanical classifiers. The obtained +0.5 mm bauxite concentrate are suitable for blending with the +1 mm concentrate of the current plant. The study results showed that recovery of fine bauxite ore particles -1mm from the plant tailings may produce additional amount of valuable concentrate to ensure the supply requirements to the alumina plant and also add some values to the effective mineral resource utilization and bring some economic efficiency.
An overview of lithium recycling methods from battery wastes
Authors: Phung Thuat Tien , Tran Duoc Van ,   Mining Faculty, Hanoi University of Mining and Geology, Vietnam
Published: December 2021

Due to the rapid development of technology and the increasing demand for energy and energy storage of electronic devices, billions of lithium batteries are produced every year. Due to the dominant capacity of storage as and super safety, lithium batteries are gradually replacing conventional batteries and otherelectrochemical batteries. Therefore, collecting and handling the used batteries should be the central concern due to their tremendous impact on the environment. This paper presents lithium recycling methods which are being studied and deployed for recovery of valuable metals from lithium battery wastes. Further directions and headings towards the researches for assessing of their application in the future are also proposed.
Some mineral - chemical composition results of titanium ore from the red sand layer in Binh Thuan area
Authors: Nguyen Gam Hong Thi , Bui Bac Hoang , Nhu Dung Kim Thi ,   National institute of Mining - Metallurgy Science and Technology  Centre for Excellence in Analysis and Experiment,, Hanoi University of Mining and Geology  Department of Mineral Processing, Hanoi University of Mining and Geology
Published: December 2021

Binh Thuan is an area with great potential for titanium ore in the red sand layer. In previous studies, a suitable scheme of mineral processing and types of equipment had been designed for improving the quality of titanium ore concentrate. However, the existence of manganese in Binh Thuan ilmenite has not been clarified, and therefore, an effective method of separating Mn from ilmenite has not yet been proposed. In this study, X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM-EDS), and Raman spectroscopy method are used to determine the mineral-chemical composition of Binh Thuan ilmenite. The analytical results show that in the study area of ilmenite ore, there was a certain proportion of Mn in the Binh Thuan ilmenite ore with an average of about 3.0%. Manganese is found to exist as a partial isomorphic replacement between Mn2+ and Fe2+ ions in ilmenite mineral crystals, creating an intermediate mineral ilmenite-pyrophanite with the formula (Fex,Mn1-x)TiO3. The obtained research results contribute to the orientation in the separation process, in removing Mn effectively from Ti concentration ore.
U - Pb zircon age of gabbro and plagiogranite in Hiep Duc, Quang Nam and their geological significances
Authors: Ngo Thanh Xuan , Bui Hau Vinh , Tran Hai Thanh , Phan Binh Van , Nguyen Hanh Hong Thi ,   Faculty of Geosciences and Geoengineering, Hanoi University of Mining and Geology, Vietnam  Vietnam Institute of Geosciences and Mineral resources, Vietnam
Published: December 2021

The gabbro and plagiogranite magmas of the Ngoc Hoi and Dieng Bong complexes are mainly distributed in the northern part of the Kon Tum block. They were previously considered parts of the Tam Ky - Phuoc Son ophiolite complex. In this study, 02 samples of gabbro and plagiogranite were collected from the Hiep Duc area. Petrographic characteristics showed that the rocks were highly foliated and weakly metamorphosed; the schist formed after the crystallization of the rocks. U - Pb zircon age dating from the gabbro rocks as 497.7±1.4 Ma, similar to the plagiogranite age of 498.0±1.3 Ma. The available results in the northern Kon Tum block and Laos indicate the existence of magma series formed during the Late Cambrian period that is probably extended from the northern Kon Tum block to the northeastern part of Laos. The research results on the northern Kon Tum block also confirmed two types of magma in the area: island - arc magma complex and ophiolite type magma complex.
Competitiveness of economic zones and industrial zones: A comparative study between Vietnam and ASEAN countries
Authors: Le Le Thi , Nguyen Hieu Tien , Le Chien Minh , Nguyen Cuong Quoc ,   Thu Dau Mot University, Binh Duong, Vietnam  Board of Management, Nghi Son economic zone, Thanh Hoa, Vietnam  Agency for Enterprise Development, Ministry of Planning and Investment, Vietnam
Published: December 2021

Competitiveness plays a crucial role in attracting investors and supporting them to operate effectively when investing in economic zones and industrial zones (EZs, IZs). This study is conducted to compare the competitiveness of EZs and IZs in Vietnam to those in other ASEAN countries. This points out the strengths that need to be promoted, weaknesses that need to be overcome for the EZs and IZs in Vietnam. Both qualitative and quantitative research methods are applied. Data is collected from many reliable sources such as reports of the World Bank (WB), United Nations Conference on Trade and Development (UNCTAD). Data screening, processing and analyzing give the following specific results: Firstly, the ability to support business start-ups, tax and social obligations, and support to resolve corporate bankruptcy are considered as the biggest weaknesses of the EZs and IZs in Vietnam. Secondly, the ability to support various types of permits, support for access to input resources and credit access are the areas that need to be further improved in the future.
Cr - spinel and clinopyroxene compositions from metagabbro of Nui Ngoc complex in Tam Ky area: evidence of island - arc magma
Authors: Ngo Thanh Xuan , Nguyen Du Khac , . Dao Anh Vu , Pham Chi Thi , Nguyen Hanh Hong Thi , Pham Dung Ngoc ,   Faculty of Geosciences and Geoengineering, Hanoi University of Mining and Geology, Vietnam  Graduate Institute of Geophysics, National Central University, Taiwan Vietnam Institute of Geosciences and Mineral Resources, Vietnam
Published: December 2021

The hornblende and biotite - bearing metagabbro of the Nui Ngoc complex were exposed into a few small blocks in the southwest Tam Ky city and were viewed as parts of the Tam Ky - Phuoc Son ophiolitic complex (TPO). These rocks were undergone mylonitic deformation and metamorphism. The rocks consist mainly of orthopyroxene, clinopyroxene, plagioclase, olivine, hornblende, biotite and very few microscopic Cr - spinel. The clinopyroxene and Cr - spinel minerals were analyzed for their composition by EPMA, the results showed that: (1) The clinopyroxenes have low Al2O3 (3,2÷3,5 wt %), TiO2 (0,70÷0,82 wt %) contents and (2) the Cr - spinels have low TiO2 (0,23÷0,58 wt %) content and Mg#100* (Mg/ (Mg+Fe2+)) (32÷42) but has medium Cr# (Cr/ (Cr+Al)) (45÷52).These features are similar to those of rocks formed in anoceanic - oceanicsubduction zone that was reported for the plagiogranite of Dieng Bong complex nearby. This study results combined with previous research results in the Tam Ky - Phuoc Son suture zone show the existence of island arc, continental arc, and MOR - magmatic types.
Variation of sediment provenance at the 09 - 1 Block, Cuu Long Basin: their significance in assessing the Oligocene - Miocene reservoir quality
Authors: Nguyen Anh Lam , Nguyen Tung Thanh , Hoang Long Van , Bui Dung Viet , Nguyen Hieu Trung , Nguyen Anh Tuan , Bui Phuong Ngoc Thi , Nguyen Trieu Tan , Trinh Trung Thanh ,   Russia-Vietnam Joint Venture, Vietsovpetro, Vietnam  Vietnam Petroleum Institute, Vietnam  VPI-Lab, Vietnam Petroleum Institute, Ho Chi Minh City, Vietnam  Vietnam Administration of Seas and Islands, Vietnam
Published: December 2021

The Cuu Long Basin is one of the Tertiary sedimentary basins situated on the continental shelf of Vietnam, which demonstrates the high potential of oil and gas. Apart from fractured granite reservoirs, the Oligocene - Miocene sand bodies are thought to have significant potential for forming non - structural traps. The results of the study on the composition and physical properties of the sediments derived from wells "X" and "Y", block 09 - 1, Cuu Long Basin show that there is a clear difference between the Late Oligocene and Early Miocene sandstone in the well "X", namely the Miocene sandstone shows larger particle size, higher roundness and sortness (TB: 434.2; Ro: 0.69; So: 2.22) than those of the Late Oligocene sandstone (TB: 104.28; Ro: 0.64; So: 1.46). This difference is likely attributed to the fact that the Miocene sandstone was influenced by the marine environment, which intensified the roundness and sortness. Meanwhile, the well "Y" did not show much difference in the physical parameters of the sediments between the Late Oligocene and Early Miocene age ranges. However, the grain size was slightly increased and the roundness was less during the Early Miocene. It is possible that the “Y” well is located closer to the local source. The variation in the physical parameters of the sediments, proportion of sand grains and clay minerals shows that the quality of late Oligocene reservoir is better than that of Early Miocene reservoir, and the Late Oligocene reservoir quality in the "X" well is better than that in the borehole "Y".
Geological region by multi-signal method of gravity anomaly data in central Vietnam area
Authors: Phan Hong Thi , Vladimirovich Petrov Aleksey , Do Phuong Minh , Nguyen Luu Truong ,   Faculty of Oil and Gas, Hanoi University of Mining and Geology, Vietnam  Faculty of Geology and Geophysics of Petroleum, University of Geology and Exploration named Sergo Ordzhonikidze, Moscow, Russia  Geophysicsl Division, General department of Geology and Minerals, Hanoi, Vietnam
Published: December 2021

This paper presents the research results of applying the combined method of probabilistic statistical approaches, energy density spectral correlation, two-dimensional filtering in dynamic sliding windows, full horizontal gradient and heterogeneous axis tracking method to process and interpret the Bughe gravitational anomaly field in central area Vietnam. The calculation results have shown the superiority of the twodimensional filter in dynamic sliding windows compared to the filters in fixed windows in GEOSOFT software, GMT software. According to the physical characteristics of the field, the study area was divided into 13 homogeneous classes, this result is consistent with the geological-tectonic data in the area. In the north and northeast, the stabilized rock layers are characterized by homogeneous layers that extend in the northwestsoutheast direction. In the south and southwest, there is complex tectonic activity characterized by high density rock layers overlain by low density rock layers in each fault band with different directions of development. This suggests that there may be deeply buried mineral deposits of magmatic origin in central area Vietnam.
Applied seismic attribte to study the distribution of sandstone reservoirs of D sequence, upper Oligocene sediments, CT field, Cuu Long basin
Authors: Tran Oanh Thi , Le Anh Ngoc , Pham Khanh Duy , Bui Ngan Thi , Pham Ngoc Bao , Nguyen Ha Hai Thi , Do Linh Thuy Thi , Doan San Ngoc , Hoang Quy Van ,   Faculty of Oil and Gas, PetroVietnam University, Vietnam  Faculty of Oil and Gas, Hanoi Univeresity of Mining and GeologyVietnam  NIPI, Vietsovpetro, Vietnam  Vietnam Petroleum Association, Vietnam
Published: December 2021

In this paper, the seismic attribute analysis methods in combination with well data were used to predict the distribution of the D sequence. A seismic attribute is any measurement of seismic data that enhances the visibility or quantification of geological elements or rock properties to determine the structure or depositional environment of sediment. The authors have selected the basic attributes, which are related to amplitude and frequency such as RAI, RMS, ARC length, Specdecom, Sweetness attribute. The attributes reflect quite accurately the changes in lithology, sedimentary facies, etc. from which will be possible to predict the distribution of the sand bodies. There are 02 large reservoirs discovered in the D sequence: the main reservoirs (D0 -D3) sands and minor reservoirs (D4 - D10). The study results show that the main reservoirs from D0 to D3 are widely distributed in the study area, especially in the western block and near the Con Son swell (except A well due to erosion process). Meanwhile, the reservoirs from D4 to D10 are of discontinuous distributions. Zones of high amplitude anomalies that are likely related to volcanic sediments in the study area are also delineated. The seismic attribute analysis reveals the possible distribution of high potential sand bodies (D2-D3) in the south-western and north-eastern parts that need further study.
Relationship between urban heat island and population density of districts in Ho Chi Minh City derived from Sentinel - 3 SLSTR data
Authors: Le Ha Thu Thi , Nguyen Trung Van , Nguyen Khoa Ngoc , Nguyen Phuong Dang , Vo Tuyet Thi , Nguyen Tho Giang , Pham Tung Van , Le Dinh Van ,   Faculty of Geomatics and Land Administration, Hanoi University of Mining and Geology, Vietnam  Can Tho Environment and Natural Resources Department, Vietnam  Ninh Kieu Land Registration Office, Vietnam  Lam Dong Irrigation - traffic Construction Joint Stock Company, Vietnam  Ho Chi Minh City University of Natural Resources and Environment, Vietnam
Published: December 2021

The urban heat island occurs due to the causes of the urbanization process, of which the main reason is an increase in population density leading to the changes in artificial objects on the ground surface. Recently, using the Split - Window algorithm for two thermal infrared spectral channels with wavelengths of 11 µm and 12 µm to calculate the daily surface temperature with two times of day and night serves to determine the change of land surface temperature. This method is intended to improve the reliability of the results and high technical efficiency. This study uses Sentinel - 3 SLSTR data to determine urban heat island in the districts of Ho Chi Minh City compared to areas bordering the city on May 15th 2020. In addition, population density is calculated according to the results of the census in 2020. The linear relationship between the urban heat island and population density was built with the coefficient of determination R2=0.64.