scholarly journals Phytoremediation of chromium: distribution and speciation of chromium in Typha angustifolia

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Viky Vidayanti ◽  
Devi N. Choesin ◽  
Iriawati Iriawati
Keyword(s):  
Hexavalent Chromium ◽  
Vascular Bundle ◽  
Trivalent Chromium ◽  
Typha Angustifolia ◽  
Alternative Approach ◽  
Almost All

Chromium (Cr), especially in hexavalent chromium [Cr(VI)] may contaminate water or soil and cause detrimental effects, as it is potentially carcinogenic and teratogenic. Phytoremediation using plants such as <em>Typha</em> <em>angustifolia</em> provides an alternative approach for handling Cr waste. The objective of this study was to determine the mechanism of Cr accumulation in <em>T. angustifolia</em>. Hydroponic media containing <em>T. angustifolia</em> was added with 0, 1, 5, 10 and 20 ppm of Cr (VI) (K2Cr2O7). After 15 days of treatment, distribution and speciation of Cr in roots and shoots of <em>T. angustifolia</em> were analyzed using XAS and μ-XRF. Results showed that Cr was detected in almost all parts of root and shoot at different intensities. Intensities of Cr was higher in roots (especially in the vascular bundle) than in shoot. Cr speciation in the root and shoot was found as trivalent chromium [Cr(III)] which formed as a result of Cr(VI) reduction. Based on the patterns of Cr distribution and speciation, results of this study suggest that <em>T. angustifolia</em> in this study does not reduce Cr(VI) to become Cr(III) inside the plants.

Identification of ’Effective’ Linear Joints Using Coupling and Joint Identification Techniques

1998 ◽  
Vol 120 (2) ◽  
pp. 331-338 ◽  
Author(s):  
Y. Ren ◽  
C. F. Beards
Keyword(s):  
Dynamic Properties ◽  
Real Life ◽  
Model Parameters ◽  
Coupling Technique ◽  
Alternative Approach ◽  
Identification Technique ◽  
Joint Identification ◽  
Stiff Joint ◽  
Almost All ◽  
Identification Techniques

Almost all real-life structures are assembled from components connected by various types of joints. Unlike many other parts, the dynamic properties of a joint are difficult to model analytically. An alternative approach for establishing a theoretical model of a joint is to extract the model parameters from experimental data using joint identification techniques. The accuracy of the identification is significantly affected by the properties of the joints themselves. If a joint is stiff, its properties are often difficult to identify accurately. This is because the responses at both ends of the joint are linearly-dependent. To make things worse, the existence of a stiff joint can also affect the accuracy of identification of other effective joints (the term “effective joints” in this paper refers to those joints which otherwise can be identified accurately). This problem is tackled by coupling these stiff joints using a generalized coupling technique, and then the properties of the remaining joints are identified using a joint identification technique. The accuracy of the joint identification can usually be improved by using this approach. Both numerically simulated and experimental results are presented.

An Alternative Approach for Evaluating the Binormal ROC Curve

2013 ◽  
Vol 4 (1) ◽  
pp. 1-17 ◽  
Author(s):  
R. Amala ◽  
R. Vishnu Vardhan
Keyword(s):  
Roc Curve ◽  
Error Function ◽  
False Positive Rate ◽  
True Positive Rate ◽  
Roc Curve Analysis ◽  
New Approach ◽  
Alternative Approach ◽  
Positive Rate ◽  
Almost All ◽  
Two Populations

In recent years the ROC curve analysis has got its attention in almost all diversified fields. Basing on the data pattern and its distribution various forms of ROC models have been derived. In this paper, the authors have assumed that the data of two populations (healthy and diseased) follows normal distribution, it is one of the most commonly used forms under parametric approach. The present paper focuses on providing an alternative approach for the tradeoff plot of ROC curve and the computation of AUC using a special function of sigmoid shape called Error function. It is assumed that the test scores of particular biomarker are normally distributed. The entire work has been carried out for providing a new approach for the construction of Binormal ROC curve, which makes use of Error function which can be called as ErROC curve. The summary measure AUC of the resulting ErROC curve has been estimated and defined as ErAUC. The authors have also focused on deriving the expression for obtaining the optimal cut-off point. The new ErROC curve model will provide the true positive rate value at each and every point of false positive rate unlike conventional Binormal ROC model.

scholarly journals Morphology analysis of hexavalent chromium reduction to trivalent chromium with syrup under different pH conditions

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Zi-Fang Chen ◽  
Xu Guan ◽  
Yong-Sheng Zhao
Keyword(s):  
Hexavalent Chromium ◽  
Bound State ◽  
Trivalent Chromium ◽  
Batch Experiments ◽  
Chromium Reduction ◽  
Reaction Systems ◽  
Mn Oxide ◽  
Morphology Analysis ◽  
Ph Conditions

Abstract Batch experiments were designed to ascertain the morphology and valence of chromium in the reduction of hexavalent chromium with syrup under different pH conditions. Results indicated that the syrup reduced hexavalent chromium to trivalent chromium, and the existing forms of Cr were mainly Cr(OH)3, CrOOH and CrOOH–Fe. The percentage of Fe–Mn oxide-bound state was 29.28%, 29.28%, 22.22% and 20.12%, respectively, and the percentage of organic binding state was 64.71%, 66.58%, 74.74% and 73.14%, respectively, in the reaction systems at different pH (2.0, 2.5, 3.0 5.6) conditions.

scholarly journals Distribution of chromium in rats exposed to hexavalent chromium and trivalent chromium aerosols.

1984 ◽  
Vol 22 (4) ◽  
pp. 261-277 ◽  
Author(s):  
Yasutomo SUZUKI ◽  
Katsunori HOMMA ◽  
Masayasu MINAMI ◽  
Hiroshi YOSHIKAWA
Keyword(s):  
Hexavalent Chromium ◽  
Trivalent Chromium

scholarly journals Combination of interfacial reduction of hexavalent chromium and trivalent chromium immobilization on tin-functionalized hydroxyapatite materials

2021 ◽  
Vol 539 ◽  
pp. 148227 ◽  
Author(s):  
Sebastiano Campisi ◽  
Claudio Evangelisti ◽  
Georgeta Postole ◽  
Antonella Gervasini
Keyword(s):  
Hexavalent Chromium ◽  
Trivalent Chromium

Selection and Impact Mechanism of Washing Agents for Chromium Contaminated Building Waste

2012 ◽  
Vol 178-181 ◽  
pp. 1083-1092
Author(s):  
Xing Run Wang ◽  
Yan Xia Zhang ◽  
Jian Min Shu
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Organic Acid ◽  
Hexavalent Chromium ◽  
Removal Rate ◽  
Trivalent Chromium ◽  
Acid Condition ◽  
Impact Mechanism ◽  
Removal Mechanisms

With the building wastes contaminated by chromium in Haibei Chemical Plan in China as objects, it studied the contents of total Cr and Cr (Ⅵ) of different sizes, analyzed the effect of 6 different washing agents, discussed the removal mechanisms of 6 different washing agents for Cr in various forms, and finally selected applicable washing agent. As the results, particle size had little impact on the contents of total Cr and Cr (Ⅵ); after one washing with water, the removal rate of total Cr and Cr (Ⅵ) was 75% and 78%, respectively, and after the second washing with 6 agents, the removal rate of citric acid was the highest, above 90% for total Cr and above 99% for hexavalent chromium; the pH of building wastes were reduced by citric acid, and under acid condition, hexavalent chromium was reduced to trivalent chromium spontaneously by organic acid, which led to better removal rate of acid soluble Cr and reducible Cr; due to the complexing action, citric acid had best removal rate for oxidizable trivalent chromium. In conclusion, citric acid is the most applicable second washing agent for building wastes.

scholarly journals PENINGKATAN KETERSEDIAAN NUTRISI MIKRO PADA TANAMAN: UPAYA MENGURANGI MALNUTRISI PADA MANUSIA

2018 ◽  
Vol 31 (2) ◽  
pp. 118
Author(s):  
Amalia Tetrani Sakya
Keyword(s):  
Food System ◽  
Vitamin A Deficiency ◽  
Well Being ◽  
Population Pressure ◽  
Nutritional Deficiencies ◽  
Nutrient Deficiencies ◽  
Food Ingredient ◽  
Micronutrient Intake ◽  
Alternative Approach ◽  
Almost All

<div class="WordSection1"><p><em>Malnutrition is still one of the big problems the majority of devel<strong>op</strong>ing countries including Indonesia. Malnutrition is the result of insufficient intake of available nutrients in the human diet. The availability of nutrients is mainly determined by the output of food produced from agricultural systems. Plants provide almost all the necessary vitamins and minerals, but due to low mineral content in staple crops, resulting in the intake becomes less and lead to malnutrition or lack of nutrients. Unfortunately, as a result of population pressure, a lot of the current global food system does not provide enough micronutrients to ensure adequate micronutrient intake for everyone. This has resulted in an increase in the prevalence of micro-nutrient deficiencies (for example, iron deficiency, vitamin A deficiency, and iodine), which now afflicts many poor women resources, infants and children in developing countries. To get a balanced nutrition and adequate then improve the quality of agriculture as a food ingredient indispensable. Various attempts to overcome nutritional deficiencies especially regarding micro nutrient deficiencies, such as supplementation, food fortification and diversification of the food has a lot to do, but did not provide maximum results. Another alternative approach to address the problem of shortage of micronutrients is biofortification, genetic biofortification or agronomic biofortification. This approach emerged due to health and human well-being depends entirely on the plants, either directly or indirectly.</em></p></div>

Plasma processing for surface modification of trivalent chromium as alternative to hexavalent chromium layer

2007 ◽  
Vol 201 (15) ◽  
pp. 6601-6605 ◽  
Author(s):  
Sik-Chol Kwon ◽  
Hak-Jun Lee ◽  
Jong-Kuk Kim ◽  
Eungsun Byon ◽  
George Collins ◽  
...  
Keyword(s):  
Surface Modification ◽  
Hexavalent Chromium ◽  
Plasma Processing ◽  
Trivalent Chromium ◽  
Chromium Layer
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