Determinants Influencing Liquidity of Listed Steel Firms in Vietnam

This study is conducted to investigate the impact levels of determinants influencing liquidity of listed steel firms on Vietnam Stock Exchange. Data were collected from audited financial statements of 25 listed food processing firms from 2014 to 2017. This research employs the least squares method (OLS) and tests to determine the influence of factors on the liquidity of listed sample firms. The results indicate that return on assets (ROA), operating period (AGE) and asset structure (AS) have positive impacts on the liquidity. In contrast, the firm size and debt ratio has the opposite effects. Based on the findings, a number of recommendations are proposed to increase the liquidity ratio of listed firms in the future. Keywords: Liquidity, steel firms, determinants, Vietnam Stock Exchange DOI: 10.7176/EJBM/11-7-10 Publication date:March 31st 201

Detection of a Sudan dye at low concentrations by surface-enhanced Raman spectroscopy using silver nanoparticles

Sudan dyes are red colorants banned from use for food due to their toxic properties. However, because of the cheapness, they are sometimes adulterated into food illegally. Currently surface-enhanced Raman spectroscopy (SERS) is emerging as a good method to detect residues (including trace amounts) of Sudan dyes in food. In this report we present the SERS detection of Sudan I (a type of Sudan dyes) to concentrations as low as 1 ppb, using a very simple SERS substrate, which is made from silver nanoparticles chemically deposited on silicon surface

The Photocatalytic Activity of the Bi2O3-B2O3-ZnO-TiO2 Glass Coating

Due to the low melting temperature, the glazes based on the Bi2O3-B2O3-ZnO system are used as coatings on the surface of industrial glass substrates. Moreover, the composition of these coatings does not contain PbO, meeting the optical and environmental properties requirements. In this study, TiO2 was used in the Bi2O3-B2O3-ZnO glaze system to improve its photocatalytic ability. This can be considered a four – component glass system Bi2O3-B2O3-ZnO-TiO2. The heating microscopy results show that the melting temperature of the glaze system is 606 °C. The Fourier transform infrared spectroscopy results show that the TiO2 polyhedra are located independently in the structure without participating in forming a glass network. Thanks to that, the photocatalytic properties of TiO2 are maintained. The X-ray diffraction patterns results show that the formed TiO2 nanocrystals are rutile and anatase crystals. The results of determining the band gap energy using UV-Vis show that the band gap energy of the base glaze system increases with the addition of TiO2. The methylene blue decomposition results also showed that the ability to decompose organic increased when TiO2 was added to the glaze coating. The characteristics such as melting temperature, microstructure, and photocatalytic capacity of Bi2O3-B2O3-ZnO-TiO2 white glazes (5 and 10 % weight of TiO2) also were indicated in this paper

Effects of experience years, gender of auditors and audit firm size on firm’ discretionary accrual management: Evidence from Vietnam

The objective of this study is to examine the effects of audit firm size and auditor characteristics on firms’ discretionary accruals management of companies listed on Ho Chi Minh Stock Exchange (HOSE) and Hanoi Stock Exchange (HNX). The results show that the gender of auditors affect discretionary accruals (DA). Female auditors approve DA at a lower value than male auditors. Number of experience years of auditors also affects restriction of DA. When the number of experience years of auditors increases, the magnitude of DA decreases, which means the quality of information on financial statements (FS) is higher. This study also reveals that the magnitude of DA is significantly lower amongst companies engaging a Big-4 specialist audit firm relative to companies using the audit services of a Non‐Big-4 specialist

ANALYSIS OF VIETNAMESE WOMEN'S BODY SHAPE FROM ANTHROPOMETRIC DATA

This study aims to classify and analyze the body shapes of Vietnamese women aged 18 to 50 using 3D anthropometric data. Research data was collected from 480 females across three regions: North, Central, and South. The five body types result from data analysis involving principal component analysis, K-means cluster analysis, numerical discriminant analysis, ANOVA test, and T-test comparison using SPSS software. Group 1, accounting for 15.23 %, represents the “short, thin, small-shouldered” body type with medium hip height and a bust-waist ratio higher than the hip-waist ratio. Group 2, accounting for 18.36 %, can be described as the “tall, slightly fat and large-shoulders” body type, characterized by high stature and hip height, with a bust-waist ratio smaller than the hip-waist ratio. Group 3, accounting for 35.94 %, falls under the category of the "Medium body type", with an average height stature and a fit body, and a bust-waist ratio equal to the waist-to-hip ratio. Group 4, representing 21.88 %, has a low hip height, a bust-waist ratio higher than the hip-waist ratio, and can be called the “short, fat, medium-shoulder” body type. Finally, group 5, which comprises 8.59 %, embodies the “too fat, average height, big shoulders” body type, featuring low hip height, and a bust - waist ratio higher than the hip-waist ratio. The method of body classification in this study is scientifically sound and reliable. The new research results can serve as a reference for the garment industry while contributing to the goal of building a virtual model library within 3D design software

Synthesis of Flower-like Silver Nanostructures on Silicon and Their Application in Surface-enhanced Raman Scattering

To enhance the intensity of surface-enhanced Raman scattering (SERS), production of metal nanostructures with sharp points, lying side by side at the nanometer level plays an extremely important role. In this paper, we report on a manufacturing process in which the silver nanoparticles with the flower-like shape have been fabricated. Such silver nanoparticles have been fabricated by chemical deposition of silver particles on silicon wafers, using a solution of hydrofluoric acid (HF), silver nitrate (AgNO3) and ascorbic acid (AsA) in water, at room temperature. During the manufacturing we found that only when the concentrations of AgNO3 and AsA are appropriate, the flower-like silver nanoparticles will form. Note that while other authors mainly made flower-like silver nanoparticles in the form of suspensions, we have created flower-like silver nanoparticles with cabbage-shape on a silicon surface. The ensembles of flower-like silver nanoparticles above were used as SERS substrates to detect crystal violet (CV) in low concentrations and good results were obtained

Development of a solar/LED lighting system for a plant tissue culture room

As the green energy, sunlight provides a friendly-environment and reduces electricity used for lighting. Our target is to enhance the use of natural energy and minimize the consumption of electricity for improving indoor environments. For this reason, a hybrid lighting system, combining sunlight with LEDs for plant tissue culture, are presented. The optical fiber daylighting system consists of three main parts: concentration, collimation beam, and transportation. The concentration part is formed by Fresnel lenses to collect and focus the sunlight into a small area by a non-imaging optical effect. The collimation part consists of optical filters and collimator lenses; the optical filters are used to reflect the ultraviolet (UV) and near infrared (NIR) regions, therefore, only the visible range of the solar light can be transmitted. The transportation part is a large-core optical fiber bundle. To increase the coupling efficiency, the collimator lens is used to expand and to collimate the focused light beam. The collimated light beam is then transported by the optical fiber bundle into a plant tissue culture room. In order to keep the plant tissue culture room at a constant illumination, a lighting control system based on LEDs is used to compensate variations of the natural light. In this paper, a prototype of optical fiber daylighting system and our proposed application will be presented.Ánh sáng mặt trời, một nguồn năng lượng xanh, được sử dụng cho chiếu sáng nhằm mang lại nguồn ánh sáng thân thiện với môi trường và giảm điện năng. Mục tiêu của chúng tôi là tăng cường sử dụng năng lượng tự nhiên và linh kiện tiêu thụ điện thấp để cải thiện môi trường ánh sáng trong nhà và giảm tiêu thụ điện cho chiếu sáng. Vì lý do này, một hệ thống chiếu sáng kết hợp ánh sáng mặt trời với đèn LED để nuôi cấy mô thực vật sẽ được trình bày. Hệ thống chiếu sáng ban ngày bằng sợi quang bao gồm ba phần chính:Bộ phận thu nhận và hội tụ ánh sáng, bộ phận chuẩn trực chùm sáng và bộ phận vận chuyển ánh sáng mặt trời tới nơi cần chiếu sáng. Phần tập trung được hình thành bởi một thấu kính Fresnel để thu thập và hội tụ ánh sáng mặt trời vào một vùng nhỏ bằng hiệu ứng quang học không tạo ảnh. Bộ phận chuẩn trực chumg sáng bao gồm bộ lọc quang học và thấu kính chuẩn trực. Bộ phận vận chuyển là các bó sợi quang lõi lớn. Bộ lọc quang học được sử dụng để phản xạ vùng cực tím (UV) và vùng hồng ngoại gần (NIR), chỉ cho phần ánh sáng nhìn thấy truyền qua. Để tăng hiệu quả ghép nối, thấu kính chuẩn trực được sử dụng để mở rộng và chuẩn trực chùm ánh sáng hội tụ. Chùm sáng chuẩn trực sau đó được vận chuyển bởi bó sợi quang vào phòng nuôi cấy mô thực vật. Để giữ cho phòng nuôi cấy mô thực vật được chiếu sáng liên tục, một hệ thống điều khiển ánh sáng dựa trên đèn LED để bù lại sự biến đổi của ánh sáng tự nhiên. Trong bài báo này, một nguyên mẫu của hệ thống chiếu sáng ban ngày bằng sợi quang và ứng dụng đề xuất của hệ thống sẽ được trình bày