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Evaluation of Some Heavy Metals in Fresh Cow’s Milk from Different Regions of Sudan
Mawia Hassan Elsaim,
Yahya Ali
Issue:
Volume 2, Issue 2, December 2018
Pages:
8-14
Received:
3 September 2018
Accepted:
14 September 2018
Published:
17 October 2018
DOI:
10.11648/j.ajaic.20180202.11
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Abstract: Heavy metals considered as the most important contamination due to the industrialization and have the influence on its existence in milk and dairy products. Milk is a very important component of human diet. The presence of heavy metals in milk at high concentration may significant health problem. The present study is achieved to investigate the concentration of some heavy metals (Cu, Cr, Cd, Pb, and Zn) in fresh cow’s milk samples available in north Sudan-Merowe using Atomic Absorption Spectrophotometer (AAS). The elements, Cd, Cr, and Pd were not detected in all the fresh cow’s milk samples under study. There is no significant in the mean concentration of Cu and Zn between the fresh cow’s milk samples of three farms where as that of Zn is significantly. Our results indicated that the mean concentration of Cu, in A 0.111, in B 0.180 and in C 0.130 mg\l respectively. However Zn in A 1.13, in B 1.42 and C 1.62 mg\l respectively. The study also focuses on prevalence of heavy metals to compared with ARD value and also with corresponding values of different countries available in literature. Our result of this paper it is so strong to meager the concentration of heavy metals and show an important.
Abstract: Heavy metals considered as the most important contamination due to the industrialization and have the influence on its existence in milk and dairy products. Milk is a very important component of human diet. The presence of heavy metals in milk at high concentration may significant health problem. The present study is achieved to investigate the con...
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Study on the Optimization of 1,3-Bis (Isocyanatomethyl) Benzene Synthesis with Bis (Trichloromethyl) Carbonate
Jianxun Dong,
Xiaoguang Zheng,
Xiaohui Li,
Xiaopeng Zhang,
Xiaoyan Feng
Issue:
Volume 2, Issue 2, December 2018
Pages:
15-19
Received:
6 September 2018
Accepted:
9 October 2018
Published:
23 October 2018
DOI:
10.11648/j.ajaic.20180202.12
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Abstract: 1,3-Bis(isocyanatomethyl)benzene is an isocyanate with high quality performance, excellent yellowing resistance and weather resistance. It has wide application in optical polymer composite materials, construction, automotive and other industries. The current production process is mainly prepared by the liquid phase reaction of m-xylylenediamine with highly toxic phosgene. Due to the particularity of phosgene, the synthesis and application of 1,3-bis(isocyanatomethyl)benzene is greatly restricted, the production threshold and the price remains high, which seriously affects the promotion of products. Exploring the non-phosgene green synthesis process for the preparation of 1,3-bis(isocyanatomethyl)benzene is one of hotspots in the isocyanate research and development. The research target of this paper is to explore a safe, convenient and environmentally friendly synthesis route for 1,3-bis(isocyanatomethyl) benzene. The synthesis optimization of 1,3-Bis(isocyanatomethyl) benzene from m-xylylenediamine and bis(trichloromethyl) Carbonate was comprehensively studied. Factors such as molar ratio of raw materials, reaction temperature, reaction time and nitrogen rate were also studied. The optimal conditions were as follows: the molar ratio of m-xylylenediamine to bis(triehloromethyl)carbonate was 1.2:1.0, the nitrogen gas velocity was 8 mL·min-1, the reaction temperature was 125°C and the reaction time was 8.0 hours. Under the optimum condition, the 1,3-Bis (isocyanatomethyl) benzene yield was 83.35%. The reaction mechanism and the key steps involved in the reaction process were also deeply analyzed.
Abstract: 1,3-Bis(isocyanatomethyl)benzene is an isocyanate with high quality performance, excellent yellowing resistance and weather resistance. It has wide application in optical polymer composite materials, construction, automotive and other industries. The current production process is mainly prepared by the liquid phase reaction of m-xylylenediamine wit...
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Effect of Salinity on Swelling Behaviors of Superwater Absorbent Hydrogel Prepared from Carboxymethyl cellulose/Acrylamide Blends by Gamma Radiation
Salma Sultana,
Md. Saifur Rahaman,
Shah Md. Marzuk Hasnine
Issue:
Volume 2, Issue 2, December 2018
Pages:
20-26
Received:
5 September 2018
Accepted:
18 September 2018
Published:
25 October 2018
DOI:
10.11648/j.ajaic.20180202.13
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Abstract: Polysaccharide-based hydrogels act like smart materials and exhibit a wide range of properties that can be utilized for several applications. Polysaccharide-based super water absorbent (SWA) hydrogel was prepared from an aqueous solution of carboxymethylcellulose (CMC)/acrylamide (AAm) Using gamma radiation from a Co-60 gamma source at room temperature (~27°C). Functional groups of the prepared hydrogel were characterized in terms of Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR). The swelling of the SWA in water and the saline solutions (NaCl, CaCl2, and AlCl3) was examined. It was found that the swelling value of the SWA in water is higher (27900%) than those of in the saline solutions (2074% in NaCl, 1718% in CaCl2 and 796% in AlCl3). Results also indicated that the swelling capacity of SWA in saline solution decreases with an increased charge of cation in salt. Swelling ratio in NaCl solution was the highest which was 26, followed by 12.48 in CaCl2 and 6.22 in AlCl3 solution. A comparative swelling study was done by changing the cationic size of the same group elements (between KCl and NaCl). This study suggested that the swelling of the SWA depends upon the cationic size. Compared to the swelling of 2074% in NaCl solution, the swelling in KCl was found to be slightly higher (2442%). This behavior can be attributed to the charge screening effect for monovalent cations, as well as the ionic crosslinking of the SWA with the multivalent cations.
Abstract: Polysaccharide-based hydrogels act like smart materials and exhibit a wide range of properties that can be utilized for several applications. Polysaccharide-based super water absorbent (SWA) hydrogel was prepared from an aqueous solution of carboxymethylcellulose (CMC)/acrylamide (AAm) Using gamma radiation from a Co-60 gamma source at room tempera...
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Investigation of CFC Substitutes to Arrest Ozone Depletion
Issue:
Volume 2, Issue 2, December 2018
Pages:
27-31
Received:
3 September 2018
Accepted:
18 September 2018
Published:
27 October 2018
DOI:
10.11648/j.ajaic.20180202.14
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Abstract: Ozone is a molecule containing three oxygen atoms which is blue in colour and has a strong odour. Ozone is considered as helpful in the stratosphere and harmful substance in the troposphere. Most atmospheric ozone is concentrated within the stratosphere, about 15-30 km above the Earth’s surface. Chlorofluorocarbons (CFCs) are a family of chemical compounds developed back in the 1930's as safe, non-toxic, non-flammable alternative to dangerous substances like ammonia for purposes of refrigeration and spray can propellants. Their usage grew enormously over the years. One of the elements that constitute CFCs is chlorine. Very little chlorine exists naturally in the atmosphere. But it turns out that CFCs are an excellent way of introducing chlorine into the ozone layer. The ultraviolet radiation at this altitude breaks down CFCs, freeing the chlorine. Under the suitable conditions, this chlorine has the potential to destroy large amounts of ozone. This has indeed been observed, especially over Antarctica. Since the cognizance of adverse influence of halogenated refrigerants in the stratosphere and in troposphere, as proclaimed at the Montreal protocol with subsequent enactment of NASA Act in 1987, the home appliance manufacturers are seriously considering replacement of Chlorofluorocarbons (CFCs) by alternative fluids in all the factors of their ever increasing market say, on refrigerators, as a blowing agent for foams, as a cleaning agent for printed circuit boards and the like, much ahead of the EPA schedule. The paper presents a scenario of the research efforts in the field, both by individual investigators and entrepreneurs with necessary recommendations.
Abstract: Ozone is a molecule containing three oxygen atoms which is blue in colour and has a strong odour. Ozone is considered as helpful in the stratosphere and harmful substance in the troposphere. Most atmospheric ozone is concentrated within the stratosphere, about 15-30 km above the Earth’s surface. Chlorofluorocarbons (CFCs) are a family of chemical c...
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