Two New Reference Materials Based on Tobacco Leaves: Certification for over a Dozen of Toxic and Essential Elements

The preparation, certification, and characterization of two new biological certified reference materials for inorganic trace analysis have been presented. They are based on two different varieties of tobacco leaves, namely, Oriental Basma Tobacco Leaves (INCT-OBTL-5), grown in Greece, and Polish Virginia Tobacco Leaves (INCT-PVTL-6), grown in Poland. Certification of the materials was based on the statistical evaluation of results obtained in a worldwide interlaboratory comparison, in which 87 laboratories from 18 countries participated, providing 2568 laboratory averages on nearly 80 elements. It was possible to establish the certified values of concentration for many elements in the new materials, that is, 37 in INCT-OBTL-5 and 36 in INCT-PVTL-6, including several toxic ones like As, Cd, Hg, Pb, and so forth. The share and the role of instrumental analytical techniques used in the process of certification of the new CRMs are discussed

State of economic immigrants in Hong Kong: problems and discrimination against national minorities based on example of Indonesian and Philippine domestic workers

Celem niniejszej pracy dyplomowej jest omówienie statusu ekonomicznych imigrantów w Hongkongu na przykładzie filipińskich i indonezyjskich pomocy domowych. Pracę rozpoczyna przedstawienie różnych rodzajów imigrantów: ekspatriantów, imigrantów z Chin kontynentalnych, zagranicznych pomocy domowych, uchodźców, azylantów i nielegalnych imigrantów. Szczegółowo zostały omówione prawa imigrantów na podstawie Ustawy Zasadniczej Hongkongu. Zwrócono uwagę również na politykę Hongkongu mającą na celu pozyskania konkretnej grupy cudzoziemców. Następnie ukazano współczesne problemy, z jakimi muszą mierzyć się imigranci na co dzień: dyskryminacja, bariera językowa i problemy z asymilacją. Poruszona została również kwestia nastrojów Hongkończyków wobec imigrantów. Szczegółowo została opracowana kwestia zagranicznych pomocy domowych. Pod uwagę zostało wzięte rozporządzenie rządu Hongkongu, czynniki zachęcające i zniechęcające do wyjazdu do pracy, życie codzienne i wzajemne wsparcie. Całość analizy została przeprowadzona w kontekście informacji zebranych na temat imigrantów oraz własnej obserwacji podczas pobytu w Hongkongu.The aim of this thesis is to discuss the economic status of immigrants in Hong Kong on the basis of Philippine and Indonesian domestic help. The work begins with a presentation of different types of immigrants: expatriates, continental Chinese immigrants, foreign domestic help, refugees, asylum seekers and illegal immigrants. The rights of immigrants under the Hong Kong Basic Law are discussed in detail. Attention was also drawn to Hong Kong's policy to attract a specific group of foreigners. Then, the contemporary problems faced by immigrants in their daily lives were presented: discrimination, language barrier and problems with assimilation. The question of the Hong Kong people's attitudes towards immigrants was also raised. The issue of foreign domestic servants has been addressed in detail. The Hong Kong Government Regulation, incentives and disincentives to go to work, daily life and mutual support have been taken into account. The whole analysis was carried out in the context of information collected on immigrants and on my own observations during stay in Hong Kong

Microwave assistant synthesis of calcium phosphate minerals using hen’s eggshells as a calcium source

In this study raw hen’s eggshells were used as a calcium source for calcium phosphate mineral synthesis. The materials composed of brushite and different amounts of HA (hydroxyapatite) and β-TCP (β-tricalcium phosphate) with the needle-like, sheet-like and hexagonal structures were synthesized in the presence of the microwave. It was found that the time of microwave action, temperature and initial pH are parameters affecting the morphology and composition of the obtained materials, i.e. the increasing duration of MW exposure increases the amount of HA increases, whereas the temperature increase causes an increase in the contents of brushite and β-TCP. The lowering of initial pH leads to an increase in the brushite content

Zeta Potential of Nanosilica in 50% Aqueous Ethylene Glycol and in 50% Aqueous Propylene Glycol

A sufficient amount of ionic surfactants may induce a zeta potential of silica particles dispersed in water–glycol mixtures of about 100 mV in absolute value. Nanoparticles of silica were dispersed in 50-50 ethylene glycol (EG)–water and 50-50 propylene glycol (PG)–water mixtures, and the zeta potential was studied as a function of acid, base, and surfactant concentrations. The addition of HCl had a limited effect on the zeta potential. The addition of NaOH in excess of 10−5 M induced a zeta potential of about −80 mV in 50% EG, but in 50% PG the effect of NaOH was less significant. The addition of CTMABr in excess of 10−3 M induced a zeta potential of about +100 mV in 50% EG and in 50% PG. The addition of SDS in excess of 10−3 M induced a zeta potential of about −80 mV in 50% EG and in 50% PG. Long-chained analogs of SDS were even more efficient than SDS, but their application is limited by their low solubility in aqueous glycols

Synthesis of hydroxyapatite derived from agricultural waste and its applications as an adsorbent for heavy metal removal from wastewater

 The presence of heavy metals in aquatic systems can be harmful to living species. Heavy metals are not biodegradable, and their tendency to accumulate in living organisms often causes different, undesirable consequences. Therefore, removing these impurities from wastewater has become one of the key issue related to environmental protection [Babel and Kurniawan 2004].There are many methods developed to remove heavy metals from wastewater and adsorption is one of the most popular one. Despite of the diversity of these technologies there is still a need to develop methods that do not require a large financial input [Hegazi 2013, Renu et al. 2017].The most important features that determine materials used as adsorbent is their low cost, biocompatibility and environmental friendly nature and hydroxyapatite presents all of them. Moreover, hydroxyapatite particles are characterized by high specific surface area and simple method of synthesis. It is also reported that it can be obtained from agricultural waste based on calcium like eggshells [Akram et al. 2014].The aim of this paper is to show and compare different methods of hydroxyapatite synthesis using eggshells as a source of calcium and it sorption capacity due to different metal cations from aqueous solution

Synthesis and Characterization of Calcium Phosphate Materials Derived from Eggshells from Different Poultry with and without the Eggshell Membrane

Calcium phosphate materials such as hydroxyapatite (HA) or tricalcium phosphate (β-TCP) are highly attractive due to their multitude of applications in bone replacement as well as their environmental and ecological credentials. In this research, quail, hen, duck, and pigeon eggshells were used as a calcium source to obtain calcium phosphate materials via the environmentally friendly wet synthesis. Using the eggshells with the organic membrane, the biphasic calcium phosphate materials composed mainly of HA were obtained. The second mineral phase was β-TCP in the case of using quail, hen, and pigeon eggshells and octacalcium phosphate (OCP) in the case of duck eggshells. The HA content in the obtained materials depended on the amount of membrane in the eggshells and decreased in the order of pigeon, duck, hen, and quail eggshells. The eggshell membrane removal from the eggshells caused the reduced content of HA and the presence of the more soluble β-TCP or OCP phase in the obtained materials. The calcium ions release profile in the PBS buffer indicates the potential biomedical application of these materials

Development of Analytical Procedures for Chemical Characterization of Substrates for the Production of TRISO Coated Particles as Nuclear Fuel in High Temperature Gas-Cooled Reactors

High temperature gas-cooled reactors have recently gained importance as a source of electricity and process heat. Nuclear fuel used in these reactors consists of TRISO (TRiple coated ISOtropic) coated particles, where spherical grains of UO2 or UC2 or UCO kernel are covered with four successive layers consisting of pyrolytic carbon and silicon carbide. Of great importance is the chemical purity of reagents and substances used for the production of TRISO coated fuel particles. Analytical techniques ensuring the determination of elements at trace levels are inductively coupled plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA). They were applied in this work for the chemical characterization of substrates used for TRISO fuel production. Two analytical procedures were developed: the first, where materials are analyzed using ICP-MS, and the second with the aid of NAA. Successive stages of these procedures are described with details. Results of quantitative chemical analysis of examined substances are reported as well as detection limits for the investigated elements. Moreover, the expanded uncertainties estimated for the determined elements while employing the devised analytical procedures are presented

Optimization of adsorptive removal of α-toluic acid by CaO2 nanoparticles using response surface methodology

The present work addresses the optimization of process parameters for adsorptive removal of α-toluic acid by calcium peroxide (CaO2) nanoparticles using response surface methodology (RSM). CaO2 nanoparticles were synthesized by chemical precipitation method and confirmed by Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) analysis which shows the CaO2 nanoparticles size range of 5–15 nm. A series of batch adsorption experiments were performed using CaO2 nanoparticles to remove α-toluic acid from the aqueous solution. Further, an experimental based central composite design (CCD) was developed to study the interactive effect of CaO2 adsorbent dosage, initial concentration of α-toluic acid, and contact time on α-toluic acid removal efficiency (response) and optimization of the process. Analysis of variance (ANOVA) was performed to determine the significance of the individual and the interactive effects of variables on the response. The model predicted response showed a good agreement with the experimental response, and the coefficient of determination, (R2) was 0.92. Among the variables, the interactive effect of adsorbent dosage and the initial α-toluic acid concentration was found to have more influence on the response than the contact time. Numerical optimization of process by RSM showed the optimal adsorbent dosage, initial concentration of α-toluic acid, and contact time as 0.03 g, 7.06 g/L, and 34 min respectively. The predicted removal efficiency was 99.50%. The experiments performed under these conditions showed α-toluic acid removal efficiency up to 98.05%, which confirmed the adequacy of the model prediction