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Ethnic differences have previously been reported for type 2 diabetes.We aimed at assessing the potential differences between Caucasian and Japanese subjects ranging from normal glucose tolerance (NGT) to impaired glucose tolerance (IGT) and to type 2 diabetes.This was a cross-sectional study with oral glucose tolerance tests to assess β-cell function, hepatic insulin extraction, and insulin sensitivity.PARTICIPANTS included 120 Japanese and 150 Caucasian subjects.Measures of β-cell function, hepatic extraction, and insulin sensitivity were assessed using C-peptide, glucose, and insulin minimal models.Basal β-cell function (Φ(b)) was lower in Japanese compared with Caucasians (P.01). In subjects with IGT, estimates of the dynamic (Φ(d)) and static (Φ(s)) β-cell responsiveness were significantly lower in the Japanese compared with Caucasians (P.05). In contrast, values of insulin action showed higher sensitivity in the Japanese IGT subjects. Hepatic extraction was similar in NGT and IGT groups but higher in Japanese type 2 diabetic subjects (P.01). Despite differences in insulin sensitivity, β-cell function, and hepatic extraction, the disposition indices were similar between the 2 ethnic groups at all glucose tolerance states. Furthermore, the overall insulin sensitivity and β-cell responsiveness for all glucose tolerance states were similar in Japanese and Caucasians after accounting for differences in body mass index.Our study provides evidence for a similar ability of Japanese and Caucasians to compensate for increased insulin resistance.

For the quantitative analyses of evolved CO2and H2O during the thermal decomposition of solids, calibration curves, i.e. the amounts of evolved gases vs. the corresponding peak areas of mass chromatograms measured by TG-MS, were plotted as referenced by the reaction stoichiometry of the thermal decomposition of sodium hydrogencarbonate NaHCO3. The accuracy and reliability of the quantitative analyses of the evolved CO2and H2O based on the calibration curves were evaluated by applying the calibration curves to the mass chromatograms for the thermal decompositions of copper(II) and zinc carbonate hydroxides. It was indicated from the observed ratio of evolved CO2and H2O that the compositions of copper(II) and zinc carbonate hydroxides examined in this study correspond to mineral malachite, Cu2CO3(OH)2, and hydrozincate, Zn5(CO3)2(OH)6, respectively. Reliability of the present analytical procedure was confirmed by the fairly good agreement of the mass fraction of the evolved gases calculated from the analytical values with the total mass-loss during the thermal decompositions measured by TG.

As one of the typical examples of producing an amorphous dehydration product, the thermal dehydration process of K2B4O7·4H2O was subjected to thermoanalytical and morphological studies. An anhydrous glass was formed via three distinguished dehydration stages. The overall thermal dehydration process was characterized as a self-induced sol-gel process to form anhydrous glass. The as produced anhydrous glass exhibited glass transition at around 700 K and subsequently crystallized via two consecutive exothermic peaks at around 770 and 900 K. The final crystallization product, triclinic K2B4O7, melted at 1072 K.

By reviewing various microscopic studies on the mechanisms of the thermal dehydration and/or decomposition reactions of inorganic solids, the physico-geometric and chemical features of the solid-state reactions were investigated. A model of reaction interface and a classification of interfacial chemical behavior for the thermal dehydration of solids, which have extensively been studied by professors Galwey and Brown, were introduced in order to evaluate the significance of such mechanistic understandings on the solid-state reactions. The meanings of the kinetic models and kinetic equations, which have been employed conventionally for analyzing the overall kinetics of solid-state reactions, were discussed in relation to the complicated physico-geometric and chemical behaviors of the solid-state reactions revealed by the mechanistic investigations. Possible extensions of the conventional kinetic theory by incorporating various physico-geometric and chemical features were examined for an advanced kinetic understanding of the solid-state reactions. The kinetic data required for the advanced kinetic analysis of the solid-state reactions were discussed by emphasizing the usefulness of the controlled rate thermal analysis (CRTA). The present status and future subjects of the kinetic and mechanistic studies on the solid-state reactions were summarized briefly through the present review.

The reaction process of the thermal dehydration of dilithium tetraborate trihydrate, Li2B4O7⋅3H2O, was reinvestigated from a viewpoint of reaction kinetics. On the basis of the results of thermogravimetry, constant rate thermal analysis, powder X-ray diffractometry, infrared spectroscopy and scanning electron microscopy, it was confirmed that the reaction proceeds via three consecutive kinetic steps characterized by different activation energies. The first and second kinetic steps, accompanied by the destruction of the original crystal structure of the reactant, seem to be assigned to the surface and internal reactions, respectively. During the third kinetic step, the thermal dehydration of hydrated amorphous intermediate, produced at the second kinetic step, and crystallization of the final dehydration product, Li2B4O7, are likely to take place concurrently.

Gut lavage fluid, collected by the oral administration of an electrolyte lavage solution, was found to be an excellent and easily collectible source of abundant mucin. Furthermore, the biochemical features of mucin from patients with ulcerative colitis (UC) and Crohn's disease (CD) were investigated. The mucin was separated into four fractions by Sepharose CL-4B, Sepharose CL-2B, and DEAE Sephacel chromatography. Compared to healthy subjects, the total yields of mucin from ulcerative colitis patients were low due to a deficiency of neutral mucin, whereas those from Crohn's disease patients were high, mainly due to high-molecular-weight mucin. Fucose and sulfate content was low in ulcerative colitis, but only the former was low in Crohn's disease. The different biochemical features of mucin obtained from gut lavage fluid appear to reflect the mucosal pathological changes associated with inflammatory bowel disease.

The formation process of bayerite, from an aqueous solution of sodium aluminate through enforced decomposition of aluminate ions by introducing CO2 gas and aging with mechanical stirring, was investigated by pH measurements of the mother solution during preparation reaction and characterization of precipitates obtained at various stages of preparation. An amorphous precipitate, produced initially by the reaction of introduced CO2, transformed to bayerite via pseudoboehmite during aging. It was found that the crystalline particle size and morphology of the crystallized bayerite change depending systematically on the preparation conditions. The reaction pathway of the thermal decomposition of the synthesized bayerite was investigated by using thermoanalytical techniques.

Background: Topical pharyngeal anesthesia is generally used as a pretreatment for upper endoscopy. However its efficacy has not been established. Methods: A randomized double—blind placebo-controlled study was undertaken. Subjects were 201 patients who underwent upper endoscopy and gave informed consent. Relative risks (RR) of patient discomfort were calculated for pharyngeal anesthesia, anxiety, and other potential confounding factors by using logistic regression analyses. Results: The RR of patient discomfort on intubation was 0.56 for the anesthesia versus the placebo group (95% CI, 0.31-1.01). RR was higher in patients aged 39 or younger than in those 40 or over (RR = 2.22, 95% CI, 1.04-4.74). With subgroup analysis in those examinees less than 40 years old, the RR of patient discomfort was 0.21 for the topical anesthesia (95% CI, 0.04-0.99) versus the placebo group and 4.93 for patients undergoing upper endoscopy for the first time (95% CI, 1.13-21.60). In the first-time patients, the RR was lower in the topical anesthesia than in the placebo group (RR = 0.20; 95% CI, 0.04-0.93); it was higher in patients with a trait-anxiety score higher by 10 points than in those with a lower score (RR = 3.35, 95% CI, 1.01-11.15). With the Bonferroni correction for multiple testing of data, statistical significance is indicated by a CI of 97.5% in the subgroup analyses. Conclusions: Topical pharyngeal anesthesia appears to be effective in patients less than 40 years old and in those undergoing the procedure for the first time. A high trait-anxiety score could be a predictor of discomfort in first-time examinees. (Gastrointest Endosc 2001;53:14-8.)

The kinetic behavior of the thermal decomposition of synthetic malachite was investigated by means of CRTA under different conditions of reduced pressure, flowing gases and quasi-isobaric atmospheres. The thermal decomposition was found to proceed at lower temperatures under the influence of the self-generated gases, CO2 and H2O. From a viewpoint of chemical equilibrium, the normal and opposite effects on the overall kinetics were observed for the self-generated CO2 and H2O, respectively. The complexity of the present reaction is also reflected by the variations of the apparent kinetic parameters which depend on the applied and self-generated atmospheric conditions. The practical usefulness of CRTA when applied to a complicated thermal decomposition is discussed as exemplified by the kinetic approaches to the present reaction.

The influence of self-generated gaseous products on the kinetics and mechanism of the thermal decomposition of synthetic malachite, Cu 2 CO 3 (OH) 2 , was investigated by means of conventional TG–DTA under various atmospheric conditions, TG–MS and CRTA under a reduced atmospheric condition, and powder X-ray diffractometry of the partially decomposed sample. It was found that the sample decomposes at a lower temperature under a higher partial pressure of self-generated gases. This interesting behavior, in contrast to the general consideration of chemical equilibrium, results from catalytic action of evolved H 2 O on the crystallization of the product CuO, and from an interaction of evolved CO 2 with poorly crystallized CuO under reduced pressure.

In an attempt to show the importance of preparing extensively teaching materials for comprehensive education in thermal analysis at an undergraduate level, the significance of the teaching materials concerning the thermal analysis and kinetics of the solid-state reactions is discussed by reviewing our teaching activities at Hiroshima University. Application of the thermoanalytical techniques to thermal decomposition of basic copper(II) salts is appropriate for an introductory experiment to thermal analysis. Microscopic observations of the textural change during the thermal dehydration of inorganic salt hydrates are suitable for introducing the kinetics of solid-state reactions. A computer practice of drawing the experimental master plot enables students to understand the kinetic theory.

The reconstructive phase transformation between two polymorphs of Cs3Sb2I9has been studied kinetically by means of powder X-ray diffraction and127INQR spectroscopy. The low-temperature form of Cs3Sb2I9contains isolated dimer anions, whereas the high-temperature form consists of polyanions in which distorted SbI6octahedra form infinite layersviaiodine bridges. The activation energy required for the reconstructive phase transition was determined to be 189±5 kJ/mol, which corresponds to the energy required to break two Sb–I(bridge) bonds of the dimer anion. The mechanism of this reconstructive phase transition was discussed on the basis of their structures and kinetic parameters.

The overall kinetics of the thermal dehydration of zinc acetate dihydrate was investigated by means of isothermal mass-change measurements, complemented by microscopic observations of the reaction geometry and morphological change during the reaction. Under isothermal conditions, the compound loses its water of crystallization in a well-defined single step; Zn(CH 3 COO) 2 · 2H 2 O → Zn(CH 3 COO) 2 + 2H 2 O. The microscopic observations for the single crystals confirm that the reaction initiates at the edge surfaces of the hexagonal thin plate by nucleation and growth processes, consequently forming the reaction interface which advances inward, toward the center of the hexagon. The kinetic results obtained from the thermoanalytical measurements indicated agreement to the first-order law, in spite of the two-dimensional shrinkage of the reaction interface. This discrepancy is discussed in connection with the interactions of the elementary nucleation and growth processes at the reaction interfaces with the self-generated water vapor. The overall kinetic behavior of the crushed crystals of different particle-size fractions, under various atmospheric conditions, was investigated. The apparent kinetic results varied systematically with the sample and atmospheric conditions, accompanied by changes of the roles of surface reaction, diffusion of evolved water vapor from the reaction interface and gross diffusion of water vapor through the assemblage of sample particles.

The reaction pathway of the thermal decomposition of synthetic brochantite, Cu4(OH)6SO4, to copper(II) oxide was investigated through the detailed kinetic characterization of the thermal dehydration and desulferation processes. The dehydration process was characterized by dividing into two overlapped kinetic processes with a possible formation of an intermediate compound, Cu4O(OH)4SO4. The dehydrated sample, Cu4O3SO4, was found first to be amorphous by means of XRD, followed by the crystallization to a mixture of CuO and CuO-CuSO4 at around 776 K. The specific surface area and the crystallization behaviour of the amorphous dehydrated compound depend largely on the dehydration conditions. The thermal desulferation process is influenced by the gross diffusion of the gaseous product SO3, which is governed by the advancement of the overall reaction interface from the top surface of the sample particle assemblage to the bottom.

on kinetics have become a feature of ICTAC Congresses and are generally well-attended and result in lots of useful discussion. The Workshop at ICTAC 13 continued the tradition with about 50 attendees. The workshop was chaired by Haruhiko Tanaka and Michael Brown. Six introductory presentations were made on the subject, followed by the discussion summarized below. The six introductory speakers were: (1) Ranjit K. Verma; (2) Mike Reading; (3) Crisan Popescu; (4) Erwin Kaiserberger; (5) Mike Brown; (6) Haruhiko Tanaka.

OBJECTIVE This cross-sectional clinical study compared the pathophysiology of type 2 diabetes in Japanese and Caucasians and investigated the role of demographic, genetic, and lifestyle-related risk factors for insulin resistance and β-cell response. RESEARCH DESIGN AND METHODS A total of 120 Japanese and 150 Caucasians were enrolled to obtain comparable distributions of high/low BMI values across glucose tolerance states (normal glucose tolerance, impaired glucose tolerance, and type 2 diabetes), which were assessed by oral glucose tolerance tests. BMI in the two cohorts was distributed around the two regional cutoff values for obesity. RESULTS Insulin sensitivity was higher in Japanese compared with Caucasians, as indicated by the homeostatic model assessment of insulin resistance and Matsuda indices, whereas β-cell response was higher in Caucasians, as measured by homeostatic model assessment of β-cell function, the insulinogenic indices, and insulin secretion ratios. Disposition indices were similar for Japanese and Caucasians at all glucose tolerance states, indicating similar β-cell response relative to the degree of insulin resistance. The main determinants for differences in metabolic indices were measures of body composition, such as BMI and distribution of adipose tissue. Differences in β-cell response between Japanese and Caucasians were not statistically significant following adjustment by differences in BMI. CONCLUSIONS Our study showed similar disposition indices in Japanese and Caucasians and that the major part of the differences in insulin sensitivity and β-cell response between Japanese and Caucasians can be explained by differences in body composition.

The shape control of crystalline particles of α-FeO(OH) was performed through growth treatment in an aqueous medium and subsequent hydrothermal treatment. The samples were subjected to a thermogravimetric (TG) study. The different TG curves obtained for the samples before and after the hydrothermal treatment were explained in connection with the existence of an irregular outer surface layer on the samples before the hydrothermal trreatment. The overall decomposition kinetics of the samples after hydrothermal treatment were determined by analyzing the TG curves at different heating rates. An apparent activation energy of approx. 140 kJ mol−1 was obtained in the restricted range of fractional reaction 0.4 ≤ α ≤ 0.95, irrespective of the samples. The appropriate kinetic model functions changed from nucleation growth to reaction interface shrinkage with increasing particle size. The correspondence of the overall kinetics obtained from the thermoanalytical method with the physico-geometry of the reaction is discussed briefly.

Hydrated and anhydrous γ-FeO(OM) with different sizes and shapes of crystalline powders were prepared through an oxidative hydrolysis of iron(II) chloride solution using urea decomposition. Systematic thermogravimetric measurements under isothermal and non-isothermal conditions were performed in order to characterize kinetically the thermal dehydration and dehydroxylation processes. The dehydration of the bound water on the surface of γ-FeO(OH) observed at around 150°C obeyed the first-order law with an apparent activation energy of about 100 kJ mol −1 , being recognized as controlled by diffusional removal of evolved water vapor through the stacking assemblage of plate-like crystalline powders. As for the hydrated γ-FeO(OH), the thermal dehydroxylation process at around 280°C, subsequent to thermal dehydration of the bound water, was well characterized by the two-dimensional phase boundary controlled reaction law R 2 with apparent activation energy of about 150 kJ mol −1 , implying shrinkage of the reaction interface from the edge of the rectangular plate. The Avrami-Erofeyev A m law was estimated for the dehydroxylation process of the anhydrous samples, in which the kinetic exponents m in the A m law increased with increasing specific surface area and the aspect ratio of the rectangular plate of the sample powders.

Some early studies of the rate of solid-state reactions are briefly reviewed in connection with the later development of techniques for determining kinetic parameters under non-isothermal conditions. The fundamental kinetic equations for the non-isothermal reactions are reexamined in an attempt to increase the reliability of the kinetic parameters obtained for solid state reactions. It is suggested that reliable kinetic parameters are obtained in terms of kinetic equations with non-integral kinetic exponents. The significance of such a kinetic approach as well as the usefulness of the reduced time are discussed and illustrated by the kinetic analysis of several decompositions of solids. It is stressed that the isoconversion methods, isothermal or non-isothermal, are quite appropriate for obtaining reliable kinetic parameters and in turn for understanding the kinetics of solid state reactions in a comprehensive and sophisticated way.

As the first part of a series on kinetic studies on the thermal decomposition of iron(III) hydroxide oxide, α-FeO(OH), involved in a crustal material, banded iron formations, is subjected to thermogravimetric measurements at various constant and linearly increasing temperatures. The validity of the kinetic procedures employed in a series of kinetic studies is tested by a comparative kinetic study of the thermal decomposition of α-FeO(OH) involved in two characteristic parts of banded iron formations, in which 54.9 ± 1.2 and 44.5 ± 2.3 wt% of α-FeO(OH) are involved. Under isothermal conditions, kinetic agreement with an Avrami-Erofe'ev equation Am (m ≈ 1.5) was observed for the thermal decomposition of both samples to α-Fe2O3. The Arrhenius parameters calculated for the two samples are identical within the statistical error. For linearly increasing temperatures, the apparent activation energies calculated for these samples by a different isoconversion method were different by about 35 kJ mol−1. Kinetic agreement with A1.5 for the sample containing 54.9 wt% of α-FeO(OH) was identical to that found under isothermic conditions. The kinetics of the other sample were characterized by the larger apparent Arrhenius parameters and the kinetic agreement with the A1 law. The different kinetic behavior under non-isothermal conditions of the samples was probably due to the difference in diffusional removal of evolved water vapor, depending on the compositional difference in the two characteristic parts of banded iron formations.

The effect of sample mass on the kinetics of the non-isothermal mass-loss process of molten NH4NO3 was investigated by TG—DTG. The apparent Arrhenius parameters were shown to decrease with increasing sample mass. Using the conventional method of kinetic calculation, it was shown that the sample-mass-dependent variation in the apparent pre-exponential factor results from the use of fractional reaction in the kinetic expression. The value of the apparent activation energy varies consequently to compensate the sample-mass-dependent change in the apparent pre-exponential factor on the regime of the mutual dependence of the Arrhenius parameters; this is known as the kinetic compensation effect. The specific Arrhenius parameters that are independent of sample mass were obtained by using the specific pre-exponential factor that is independent of sample mass, instead of the apparent pre-exponential factor.

The mechanism of the thermal decomposition of potassium permanganate crystals is critically reappraised through new microscopic and kinetic observations which are discussed with due consideration of the many and extensive literature reports that relate to this solid state reaction. We identify, from electron micrographs, a crystalline product of unusual texture that is formed early in the reaction. The topography of the residual products of the completely decomposed salt was, however, irregular and no significant textural features were identified. From consideration of the published reports relating to reaction stoichiometry and the chemistry of related reactions, we conclude that the solid products contain material that is inhomogeneous, poorly crystallized and possibly non-stoichiometric. The decomposition kinetics are shown to be satisfactorily described by the Avrami—Erofe'ev equation ( n = 2) based on a nucleation-and-growth reaction model. We conclude that permanganate ions decompose in the poorly crystallized zone at the advancing KMnO 4 / product interface by an electron transfer process, in agreement with a previously published mechanism.

The degree of coordination between the kinetic information from the thermonalytical measurements and the kinetic theory of the solid-state reactions was investigated through the microscopic study of the thermal dehydration of several inorganic salt hydrates. An accommodation function was applied to the conventional kinetic model functionsf(α), in an attempt to reduce the disagreement between the actual process and the idealized one assumed in formulatingf(α). The significance of the non-integral kinetic exponent in the kinetic model function was discussed with its physico-chemical meanings.

The rate behavior of the isothermal dehydration of crushed crystals of Li 2 SO 4 · H 2 O was studied under a self-generated temperature condition by recording the mass loss and temperature deviation from the pre-set isothermal temperature. The sample temperature during the reaction was influenced by the effect of self-cooling. The rate process under such a temperature condition could be divided into three distinct stages: acceleratory, nearly constant rate, and deceleratory periods. The constant rate period was processed kinetically using the Friedman method. The apparent values of Arrhenius parameters during the constant rate process remained constant irrespective of the sample mass examined.

Effects of sample mass on the kinetics of isothermal dehydration of crushed crystals of Li2SO4·H2O were investigated using conventional TG. The process was characterized by a combination of Avrami-Erofeyev and contracting geometry models. Distribution of the fractional reaction, α, in particles within the sample assembly as well as the change in the rate of gross diffusion of the evolved water vapour appear responsible for the sample-mass-dependent kinetic parameters obtained for the system.

Thermoanalytical (TA) and hot-stage microscopic techniques were employed to investigate the complicated behaviour of the non-isothermal dehydration of single crystals of α-NiSO4·6H2O. Non-isothermal dehydration to the tetrahydrate proceeds in two stages: (1) surface nucleation and growth of nuclei, followed by advancement of reaction fronts inward; (2) random nucleation and growth near the reaction front as well as in the bulk. Corresponding TA curves were interpreted to represent diffusional removal of evolved water vapour through the surface layer created in stage (1). The dehydration process of the tetrahydrate to the monohydrate is explained on the basis of textural structures produced in the previous step. Crack formation in the surface layer and rapid escape of the water vapour were observed in this step.

For the kinetic description of the solid-state reactions, the dependence of the apparent kinetic parameters on the sample mass and/or particle size is discussed mathematically in relation to some problems on the fractional conversion a. As for the reaction proceeding according to the contracting geometry model, the use of the specific rate constant, independent of the sample mass and particle size, is recommended to obtain the sample mass-independent Arrhenius parameters. It is also pointed out that the distribution of α within the assembly of sample particles disturbs the successful use of α in the kinetic description of the solid-state reactions.

Effects of sample mass on the kinetics of isothermal dehydration of crushed crystals of Li2SO4·H2O were investigated using conventional TG. The process was characterized by a combination of Avrami-Erofeyev and contracting geometry models. Distribution of the fractional reaction, α, in particles within the sample assembly as well as the change in the rate of gross diffusion of the evolved water vapour appear responsible for the sample-mass-dependent kinetic parameters obtained for the system.

The fundamental problems in the thermoanalytical kinetics of solid state reactions were investigated as exemplified by the thermal dehydration of Li 2 SO 4 · H 2 O. Distortion of the Arrhenius parameters and their consequent interdependence are described mathematically. A possible way to increase the reliability of the thermoanalytical kinetic study is discussed in connection with the possibility of the establishment of a kinetic standard.

The synthesis of malachite CuCO3·Cu(OH)2 or Cu2CO3(OH)2 was studied through titrations of copper(II) salt solutions with a solution of sodium carbonate at different temperatures. The precipitates were characterized by TG, IR and chemical analysis. The composition varies depending on thepH of the solution and the temperature. Purer malachite was synthesized by simple mixing of a solution of copper(II) nitrate or sulfate with a solution of sodium carbonate at 50°C.

The Arrhenius parameters and kinetic obedience were determined by TG at constant temperatures as well as at linearly increasing temperatures for the thermal decomposition of sodium hydrogencarbonate. Effects of the sample size (0.5–10 mg) and the particle size on the rate behavior were examined. With such a sample size smaller than ca. 5 mg, an effect of the heating rate was not so critical as is the case with the larger sample size. The Arrhenius parameters and kinetic obedience determined by use of the Ozawa method were in excellent agreement with those determined isothermally. The activation energyE determined with ca. 1 mg of sample was nearly constant independently of the fractional reactiona. Any change in the Arrhenius parameters with different experimental conditions was dicussed in connection with the kinetic compensation effect.

Kinetic data of the title dehydration obtained from simultaneous TG-DSC measurements were compared between the single crystals and crushed crystal material. The kinetics were interpreted in relation to the reaction geometry observed by polarizing microscopy. The kinetic compensation effect established for the Arrhenius parameters evaluated by the Ozawa method was discussed in terms of the temperature interval analyzed.

Kinetic obedience and Arrhenius parameters for the isothermal and non-isothermal dehydration of crushed crystals of lithium sulphate monohydrate were determined by TG using eight methods including differential and integral methods. Different apparent Arrhenius parameters were obtained by the different methods, including the differential and integral methods as well as the isothermal and non-isothermal methods. The difference in the kinetic results determined by the different methods is explained on the basis of the nature of these methods. The causation of the so-called kinetic compensation effect observed for a given dehydration reaction is discussed in connection with the reliability of TG data and the applicability of the calculation method.

The titration reaction of an NaOH solution with a copper(II) sulphate solution occurred in two steps. The first-stage precipitate, Cu(OH) 2 and/or CuO, formed above pH 7, reacted with free SO 4 2− ions and excess CuSO 4 in solution to give basic copper( II ) sulphates such as synthetic brochantite. The reaction with excess CuSO 4 was confirmed by titrating Cu(OH) 2 and CuO powders suspended in water with a copper(II) sulphate solution. These products were analysed by thermogravimetry as well as chemical methods and IR spectroscopy.

Two causes for the kinetic compensation effect (KCE) were recognized for a given solidstate reaction at various heating rates. One is due to any change in the range of reaction. This KCE is quantitative and meaningful, provided thatF(α) remains constant under the given conditions. The other is due to misestimation of the appropriate rate law, which in turn leads to a superficial KCE. It was also shown that the existence of an isokinetic point does not necessarily imply the occurrence of a meaningful KCE.

Kinetic analysis of the thermal dehydration of crushed crystals of Cu(CH3COO)2· H2O was made by use of TG and DSC curves recorded under comparable experimental conditions. Isothermal TG was also employed, and the result was compared with that obtained nonisothermally. The isothermal reaction was described by a phase-boundary controlled reaction (Rn) law, 1 −(1-α)1n = kt, with 1 < n < 2. As for the nonisothermal reaction, there was a tendency for the appropriate kinetic law determined from TG to change from an Avrami-Erofeyev (Am) law, [−ln(1-α)]1m = kt, to one of diffusion-controlled reaction (DL laws as the reaction advanced, particularly for a larger particle-size fraction of the sample. According to DSC, the nonisothermal kinetics were described exclusively by an Am law. The difference in kinetics determined from TG and DSC was explained by the nature of the two methods.

Kinetic analysis of the thermogravimetric curves obtained for the thermal dehydration of single crystalline Cu(CH3COO)2·H2O revealed that the isothermal dehydration is regulated, as a whole, by a phase-boundary controlled reaction law, Rn=kt, with 2

The effects of self cooling on the apparent kinetics of the nonisothermal dehydration of crushed crystals of lithium sulfate monohydrate were investigated using TG accompanied by DTA and power-compensation type DSC. Linearity of the sample heating rate on the TG-DSC system is much better than that on the TG-DTA. Kinetic obedience and Arrhenius parameters obtained from the TG-DTA deviate considerably from those obtained from the TG-DSC; the latter are the more accurate due to the better linearity of the sample heating rate.

The internal surfaces of crushed crystals of K2CuCl4·2H2O, dehydrated nonisothermally to various reaction fractions, were observed using a polarizing microscope. The reaction proceeds inward, through the advancement of reaction fronts, and is accompanied by some random nucleation in the bulk. The results are compared with those for the nonisothermal dehydration of single crystal K2CuCl4·2H2O (J. Phys. Chem., 92(1988)7023]. A marked difference in kinetic behavior between the two samples is explained by assuming that diffusion of the gaseous product is impeded by the outerlayer of the crystalline product. Mathematical analyses of the simultaneous TG and DSC traces at various heating rates suggest that the reaction, as a whole, is regulated by a contracting geometry law. However, an Avrami-Erofeyev law plays an important role in the early stage of the dehydration. Comparison of kinetic results, assessed from TG and DSC, favors the above assumption that the gaseous diffusion is a rate determining step, particularly at the later stages of reaction.

Chemistry. Laboratory, Faculty of Education, Hiroshima University, 1-1-1, Kagamiyama, Higashi-Hiroshima, 739-8524, Japan Manuscript received 10 July 2000 Education plays a critical role in realizing sustainable development and promoting the capability of the people to address environmental/developmental issues. On the verge of the 21st Century, educational reforms and development are placed at a high priority in many countries. In the Asia-Pacific region, a project called "Learning for a Sustainable Environment —Innovations in Teacher Education through Environmental Education" initiated by UNESCO-ACEID has contributed towards the promotion of environmental education, specifically comprehensive one in school. It is also evident that science/chemis­try is one of the most important subjects in dealing with environmental education. The relationship between human life and the environment can logically be explained through scientific/chemical skills and knowledge. Accordingly it is required that some chemistry-oriented teaching materials on comprehensive environmental education be effectively implemented in school. Chemical treatment of waste material and wastewater generated in school laboratories can be the appropriate teaching material for environmental chemistry education, because the treatment involves some typically important chemical reactions such as precipitation, neutralization, oxidation-reduction, and so on. Sonic reaction cycles for recovering several chemical compounds from wastewater involving iron, manganese, copper and so on arc useful to secondary school chemistry as well as introductory general chemistry at colleges and universities. It is important to develop chemical recycling systems for such metallic ions in school laboratories and to introduce the principle of recycling as a practice of environmental protection by students themselves. Such an approach enables students to understand chemical reactions involved and the role of chemis­try in preserving our environment, which may in turn lead to environmentally responsible attitudes and actions in their daily lives.