COPPER AND LEAD RECOVERY FROM DISCARDED PRINTED CIRCUIT BOARDS BY ELECTROLYSING LEACHED SOLUTION

Results of copper and lead recovery from discarded printing circuit boards (PCB) by acidic dissolution and electrodeposition are presented. A preliminary procedure of the recovery process is proposed with the following steps: disposal of the mounted electrical elements, cleaning, grinding, iron separation for grains screening, metal dissolution, and electrolysis. The composition analysis is performed to define suitable electrochemical parameters for recovery. XRF and AAS techniques are used for preliminary estimation of metal content in leached solution. LSV method is implemented to establish parameters for copper electrodeposition. The product quality is evaluated through XRD analysis. The high recovery efficiencies, 97.61% and 96.59 % for copper (in metallic form) and lead (in dioxide form), respectively, were reached.

On Building a Community to Exchange and Share Sustainable Fashion Applications

Sustainable development is a standard plan for peace and prosperity for people and the planet, now and in the future, set forth by the 2030 Agenda for Sustainable Development, which was adopted by all United Nations member states and agreed to in 2015. The Sustainable Development Goals (SDGs) are an urgent call to action for all developed and developing countries in relation to global cooperation. Many factors cause environmental pollution, but the fashion industry is considered by the United Nations Conference on Trade and Development (UNCTAD) as the second most polluting industry in the world. It accounts for 10% of global carbon emissions due to the energy used in production, manufacturing, and transportation. In particular, the factors that strongly affect the environment in the fashion industry are the textile materials, the fabric dyeing industry, and the rapid development of fast fashion. The data was collected through an online survey of 101 fashion consumers and interviews with nine target audiences who need to buy and sell used clothes or are interested in buying and selling used clothes or sustainable fashion. Sustainable design is not a new concept, but it is still quite strange to the Vietnamese. Consumer ignorance about sustainable consumption and the harmful effects of the fashion industry on planet Earth is a big reason why consumers constantly plunge into the shopping vortex. The problem of wasteful and unsustainable fashion consumption is a big global problem at a time when the fashion industry is gradually emerging into the sustainable fashion movement. This is an opportunity to build a community by connecting consumers through their essential needs, helping them raise awareness, change their behavior, and make each individual part of a sustainable fashion community. They are thus contributing to sustainable development in the future. Keywords: SDGs, sustainable fashion, sustainable consumption, communit

Heavy p-Block Analogues of Dithiazolyl Radicals

This thesis commences with an introduction to the chemistry and materials properties of dithiazolyl radicals and a review of previous research on the isolobal heterocyclic phosphorus-containing derivatives, particularly dithiaphospholes and diazaphospholes. P-chloro-1,3,2-benzo-dithiaphospholes were prepared from the condensation of PCl3 and 1,2-benzodithiols in good yield. Reduction afforded 2c,2e- P-P s-bonded dimers containing a formal PII oxidation state which were characterised by X-ray diffraction. Re-oxidation generates the crystallographically characterised Phalogeno- 1,3,2-benzo-dithiaphospholes. The synthesis and structural characterisation of the isolobal P-chloro-1,3,2-benzodiazaphospholes, C6H4(NR)2PCl (R = H, Me, Et, COMe, COOMe) is described. The outcome of attempted reductive coupling was found to be sensitive to reaction conditions, affording the PII dimer alongside other decomposition products characterised by Xray diffraction. Functionalisation of the P-chloro group by salt metathesis and/or condensation was used to prepare a series of poly-cyclic structures containing two or more diazaphosphole, dithiaphosphole and dithia-arsole rings linked via bridging units which were characterised by X-ray diffraction. The paddle-wheel molecules N(C7H6S2Pn)3 (Pn = P, As) were prepared by a stepwise condensation of Li[N(SiMe3)2] with P-chloro-dithiaphosphole and As-chloro-dithia-arsole whereas the bis-triamide C6H4(NR[C6H4(NR)2P])2 was prepared from condensation of the P-chloro-diazaphosphole with ortho-C6H4(NHR)2. Treatment of P-chloro-dithiaphospholes or P-chlorochloro-benzodiazaphospholes with MCl3 (M = Al, Ga) generated a series of two-coordinate phosphenium cations whose structures were determined by X-ray crystallography. This methodology was extended to prepare the heavier dithia-arsenium and dithia-stibenium cations and the structure of the first benzodithia-arsenium cation is reported. These cations are Lewis acidic and form a series of 1:1 complexes with Ph3E (E= P, As, Sb) which are characterised by multinuclear NMR. The dithiaphosphenium cation (as its GaCl4 - salt) also forms adducts with dioxane and propylene oxide but is an efficient catalyst for the cationic ring opening polymerisation (CROP) of THF to form poly(THF), [O(CH2)4]n. The conversion rate and yield is sensitive to reaction conditions. Notably the corresponding AlCl4 - salt did not polymerise THF due to reformation of the P-chloro-dithiaphosphole and formation of the adduct, AlCl3·2THF. The related arsenium and stibenium cations show limited activity as reagents for the CROP of THF

Review of Impacts of Leadership Competence of Project Managers on Construction Project Success

Leadership - Human endeavors play an important role in all areas of socio-economic development for any country in the world. Construction investment projects need more leadership role by their own characteristics. This research aims to give an overview of the theories of project manager leadership competence, the viewpoints of evaluation of the project's success, and the views on the influence of leadership competences and the success of the project. Research on the use of reliable secondary document sources in the world is synthesized from research works, scientific reports in the field of project management. The results of this study show that there is a great deal of research literature on project manager leadership competence and the success of the project in general but not many research papers on construction projects. This research is intended to suggest further studies to determine the specific influences, from that the training direction will increase the project management competence in the field of construction

The Impact of Job Satisfaction on Job Performance of Tax Officials: An Empirical Study in Vietnam

Purpose: The level of employee satisfaction with the use of e-tax systems is a major factor influencing the success of such systems. While studies typically focus on taxpayers' perspectives, this research investigates the influence of perceived ease of use, IT background, incentives, and social influence on tax officials’ job performance, mediated by tax officials’ job satisfaction.   Theoretical framework: The research is based on the Theory of Planned Behavior (TPB) and Technology Acceptance Model (TAM) to propose the research model which analyze the impact of job satisfaction on job performance.    Design/Methodology/Approach: A quantitative approach was adopted, involving surveys administered to tax officials in Vietnam. The study analyzed 250 valid responses using Cronbach's test, Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), and Structural Equation Modeling (SEM).   Findings: The research revealed that all four factors significantly influence job performance through job satisfaction of tax officials in Vietnam. These findings provide valuable insights for tax authorities to improve job performance.   Research, Practical & Social implications: The research results contribute to other countries with similar characteristics in devising strategies to enhance employee performance. However, its limitations include its generalizability to other e-tax systems and countries. Future research with a larger sample size could bolster the applicability of these findings nationally.   Originality/Value: The research suggests tax authorities to support tax officials improve their professional skills; improve the regulations, policies on salary and bonus for tax officials; assist tax officials in using the e-tax system; implement effective communication

‘I’m not like that, why treat me the same way?’ The impact of stereotyping international students on their learning, employability and connectedness with the workplace

A significant body of literature on international education examines the experiences of international students in the host country. There is however a critical lack of empirical work that investigates the dynamic and complex positioning of international students within the current education-migration nexus that prevails international education in countries such as Australia, Canada and the UK. This paper addresses an important but under-researched area of the education-migration landscape by examining how the stereotyping of students as mere ‘migration hunters’ may impact their study and work experiences. It draws on a four-year research project funded by the Australian Research Council that includes more than 150 interviews and fieldwork in the Australian vocational education context. Positioning theory is used as a conceptual framework to analyse how generalising international students as ‘mere migration hunters’ has led to the disconnectedness, vulnerability and marginalization of the group of international students participating in this research

Red-emitting Ba2Si5N8Eu2+ conversion phosphor: A new selection for enhancing the optical performance of the in-cup packaging MCW-LEDs

In this research, the influence of the red-emitting Ba2Si5N8Eu2+ convention phosphor on the optical performance of the 7,000K and 7,700K in-cup packaging multi-chip white LEDs (MCW-LEDs) is investigated. The effect of the red-emitting Ba2Si5N8Eu2+ convention phosphor is demonstrated based on Mie Theory by Mat Lab and Light Tools software. The research results indicated that the optical performance of MCW-LEDs was crucially affected by the red-emitting Ba2Si5N8Eu2+ phosphor's concentration. This paper provides an essential recommendation for selecting and developing the phosphor materials for MW-LEDs manufacturing.Web of Science51art. no. 148615

汉越人称指示语的相比研究 = A comparision of person deixis in Chinese and Vietnamese

Master'sMASTER OF ART

THÀNH PHẦN LOÀI, PHÂN BỐ VÀ MỐI QUAN HỆ GIỮA QUẦN XÃ CÁ BỐNG VỚI CÁC YẾU TỐ MÔI TRƯỜNG VÀ SINH CƯ Ở VÙNG HẠ LƯU SÔNG THU BỒN, TỈNH QUẢNG NAM

The study was conducted at three sites representing large variation in gradient of salinity from very low (Thanh Ha) to medium (Cam Nam) and high (Cam Thanh) in rainy (12/2015) and dry seasons (6/2016) in downstream area of Thu Bon river. At each site, goby species were sampled with traps and measurements of enviromental factors (pH, temperature, salinity, dissolved oxygen) and habitats (cover of freshwater weeds-grass, nypa palm-seagrass, sand-mud, mud-sand) were conducted at the 3 sites mentioned above. A total of 14 species belonging to 2 families Gobiidae (8 species) and Eleotridae (6 species) were recorded in rainy and dry seasons, in which the brackishwater site (Cam Thanh) supported the higher number of species (12 species) compared to the transitional site (Cam Nam: 6 species) and the freshwater site (Thanh Ha: 10 species). Results of annalyzing canonical correspondence between goby communities and the enviromental factors and habitats indicate that the distribution of goby community was mainly influenced by pH, salinity, dissolved oxygen and benthic cover of freshwater seaweeds-grass.Nghiên cứu được tiến hành tại 3 khu vực đặc trưng cho sự thay đổi về phông (gradient) độ mặn tầng đáy, từ rất thấp (Thanh Hà) đến trung bình (Cẩm Nam) và cao (Cẩm Thanh) vào 2 đợt đại diện cho mùa mưa (tháng 12/2015) và mùa khô (tháng 6/2016) tại vùng hạ lưu sông Thu Bồn. Tại mỗi khu vực, tiến hành thu mẫu khai thác của nghề lờ (lồng) và đo các yếu tố môi trường cơ bản (pH, nhiệt độ, độ mặn, độ oxy hòa tan) và sinh cư (độ phủ của rong-cỏ nước ngọt, dừa nước-cỏ biển, bùn-cát và cát-bùn) tại 3 trạm đại diện, đồng kết hợp thu mẫu tại các điểm lên cá. Kết quả khảo sát đã ghi nhận được 14 loài thuộc 8 giống của 2 họ cá bống trắng Gobiidae (8 loài) và cá bống đen Eleotridae (6 loài) trong đó khu vực Cẩm Thanh có số lượng loài nhiều nhất (12 loài) so với Thanh Hà (10 loài) và Cẩm Nam (6 loài). Nhìn chung, số lượng loài cá bống ghi nhận được trong mùa mưa cao hơn so với mùa khô tại cả 3 khu vực khảo sát. Kết quả phân tích mối tương quan giữa thành phần loài và độ phong phú của cá bống với các yếu tố môi trường và sinh cư cho thấy sự phân bố của quần xã cá bống chịu sự chi phối của pH, độ mặn, oxy hòa tan và độ phủ của rong-cỏ nước ngọt