The development of the globally harmonized system (GHS) of classification and labelling of hazardous chemicals

The hazards of chemicals can be classified using classification criteria that are based on physical, chemical and ecotoxicological endpoints. These criteria may be developed be iteratively, based on scientific or regulatory processes. A number of national and international schemes have been developed over the past 50 years, and some, such as the UN Dangerous Goods system or the EC system for hazardous substances, are in widespread use. However, the unnecessarily complicated multiplicity of existing hazard classifications created much unnecessary confusion at the user level, and a recommendation was made at the 1992 Rio Earth summit to develop a globally harmonized chemical hazard classification and compatible labelling system, including material safety data sheets and easily understandable symbols, that could be used for manufacture, transport, use and disposal of chemical substances. This became the globally harmonized system for the Classification and Labelling of Chemicals (GHS). The developmental phase of the GHS is largely complete. Consistent criteria for categorising chemicals according to their toxic, physical, chemical and ecological hazards are now available. Consistent hazard communication tools such as labelling and material safety data sheets are also close to finalisation. The next phase is implementation of the GHS. The Intergovernmental Forum for Chemical Safety recommends that all countries implement the GHS as soon as possible with a view to have the system fully operational by 2008. When the GHS is in place, the world will finally have one system for classification of chemical hazards.     

Copper complexes of Di-, Tri- and hexapeptides containing N2, N4-diaminobutyric acid

Sixteen copper complexes of di-, tri- and hexapeptides containing N², N⁴-diaminobutyric acid are studied spectrophotometrically. The λ_max, and colour of the complex is independent of the sequence of the amino acid in any of these peptides. The N⁴-amino group of the A₂bu-residues do not participate in complex formation. However, the hydrazide group of di- and tripeptide hydrazides participates in complex formation.     

Influence of sintering temperature on microstructural changes of ceramic Raschig ring

The thermal behavior of Illitic-kaolinitic clay for manufacturing of low porosity ceramic Raschig rings was characterized during the sintering process. The samples were shaped by extrusion method and fired at different temperatures from 1,100 to 1,300 °C. The main physical-chemical transformations were studied by evaluating changes in shrinkage, water absorption, porosity, mechanical strength, microstructure and mineralogical compositions. The optimum sintering condition was found to obtain maximum mechanical strength. Chemical resistance of ceramic Raschig rings also was determined according standard method. It was shown that the better chemical resistance could be attributed to the different mineralogical compositions, in particular with presence of mullite phase.     

A rapid method for evaluation of the oxidation stability of castor oil FAME: influence of antioxidant type and concentration

The oxidation stability of castor oil fatty methyl ester (FAME), doped with four different phenolic antioxidants, was evaluated using a rapid method of thermal and air-contact degradation. The methodology is based on the induction times observed when the samples are contacted with pure oxygen at elevated pressures and temperatures. The results indicate different performances of the antioxidants as well as synergisms between antioxidants and biodiesel. In general, the addition of antioxidants increased from 6-15 times the stability of castor oil FAME., with BHA (butylated hydroxyanisol) showing the best results for improving antioxidation in castor oil biodiesel.     

具有双对称截面的双轴加载薄壁楔形梁柱的性能分析

纵向加劲肋可以有效提高方形或矩形薄壁钢管混凝土柱的整体性能。主要讨论轴压下加劲方形短柱的非线性分析与设计。运用有限元程序ABAQUS进行非线性分析。关于荷载-位移曲线和极限强度的试验与分析结果具有良好的一致性。运用这个模型同时也对柱的性能进行了研究,讨论板的宽厚比限值和加劲肋刚度需求,以及运用现有规范预测加劲复合柱承载能力的可行性。     

Effect of pre-treatment and hydraulic retention time on biohydrogen production from organic wastes

This study investigated the effect of pre-treatment and hydraulic retention time (HRT) on biohydrogen production from organic wastes. Various pre-treatments including thermal, base, acid, ultrasonication, and hydrogen peroxide were applied alone or in combination to enhance biohydrogen production from potato and bean wastewater in batch tests. All the pre-treated samples showed higher hydrogen production than the control tests. Hydrogen peroxide pre-treatment achieved the best results of 939.7 and 470 mL for potato and bean wastewater, respectively. Continuous biohydrogen production from sucrose, potato and bean wastewater was significantly influenced by reducing the HRT as 24, 18 and 12 h. Sucrose and potato showed similar behavior, where the hydrogen production rate (HPR) increased with decreasing the HRT. Optimum hydrogen yield results of 320 mL-H₂/g-VS (sucrose) and 150 mL-H₂/g-VS (potato) were achieved at HRT of 18 h. Bean wastewater showed optimum HPR of 0.65 L/L.d with hydrogen yield of 80 mL-H₂/g-VS at 24 h HRT.     

Efficient recursive least squares parameter estimation algorithm for accurate nanoCMOS variable gain amplifier performances

ABSTRACT

With the aggressive scaling of integrated circuit technology, parametric estimation is a critical task for designers who looked for solutions to the challenges of some Nanoscale CMOS parameters. This paper presented the prediction of primary parameters of CMOS transistor for 16 nm to 10 nm process nodes using both of Bisquare Weights (BW) method and a novel recursive least squares (RLS) parameter estimation algorithm. The proposed RLS algorithm consists of the minimisation of a quadratic criterion relating to the prediction error in order to attain the best estimated parameters of the developed mathematical model. The obtained results thanks to the proposed RLS algorithm were better than those reached using the BW method. Comparisons between Predictive Technology Model (PTM) data and parameters estimated with RLS algorithm were made to check the validity and the consistency of the proposed algorithm. These predicted primary parameters were helpful to estimate and to optimise the performances of the Variable Gain Amplifier (VGA) which was a basic circuit element with a key role in the design of new upcoming receivers.