The CO₂ emission reduction in the cement production process is also thought to be important considering the serious global warming issue, though the amount of emission of carbon dioxide from the cement production reaction is a relatively small compared to the huge amount of its emission especially from fossil fuel use. In the present study, the possibility of the CO₂ emission reduction by substituting wollastonite for a part of limestone, the main raw material of Portland cement production, was examined. As a result, around 30% of limestone was possible to be replaced with wollastnite. And, the physical and chemical properties of the alternative cement was almost comparable to the conventional Portland cement: rather it was found that the alternative cement contained less free lime and showed better strength than the conventional one.

Annual carbon dioxide emission from cement production in Japan is about 26 million tons, accounting for 2% of the total emissions, and reducing carbon dioxide emissions in this section is important. The authors have reported that by replacing 30% of limestone, the main raw material of cement, with wollastonite, carbon dioxide emissions can be reduced without impairing the properties of produced cement. In this report, the carbon dioxide emission reduction amount by the above process was quantitatively evaluated. As a result, heat and mass balance calculation showed that the reduction of fuel consumption could be expected by replacing limestone with wollastonite in addition to the reduction in carbon dioxide emission from limestone calcination, and the total reduction of carbon dioxide emission was found to be 23.5% compared to the conventional process.

  The aim of the present paper is to demonstrate who is the first creator of the 45-degree line diagram, or the Keynesian Cross; neither Paul Samuelson (1948a) in Economics (1st ed.), Lawrence Klein (1947) in The Keynesian Revolution, Paul Samuelson (1939) in "A Synthesis of the Principle of Acceleration and the Multiplier" nor Ivar Jantzen (1935) in "Lidt planøkonomisk Teori (On the Theory of Planned Economy)," it is Michał Kalecki (1929; 1933; 1938) in "W sprawie aktywizacji bilansu handlowego (On Activating the Balance of Trade)," Próba teorii koniunktury (Essay on the Business Cycle Theory), and "The Determination of Distribution of the National Income," respectively. In inquiring into making of the 45-degree line diagram, the present study clarifies the attribute of the model which is that the national income is determined by the principle of effective demand in three equivalent views: production, distribution, and expenditure, the equilibrium national income is achieved by equilibrating saving with investment, the crowding-out effect will not occur when the national income is under the full-employment national-income level and money supply is not constant, widening income inequality decreases the national income, and the basic consumption included in the consumption function means its perspective on the economics of welfare. From the last aspect, furthermore, the Kalecki Cross (or the Matsuya Cross) of the two-sector model is easily transformed into the more standard type of the 45-degree line diagram, which is one of the three versions of the Keynesian Cross diagram in textbooks, whose differences are spotted in the treatment of the 45-degree line.