Recently, there has been a growing interest in the stabilisation of soil, with addition of cement and fly
ash. One common problem in road construction in South East Asia is soft silty clay subgrade. The
problems worsen when the water table influences the subgrade of the road. Fly ash as a waste
material can be utilised as soil stabiliser. In these studies, a soft silty clay was mixed with cement
slurry in the different proportion of fly ash and cement content.
Unconfined compression tests were used to investigate the behaviour of cement and fly ash to
stabilise soft silty clay in the Laboratory. From the results of the unconfined compression tests
indicated that by the addition of a small percentage of cementing agent, the strength of the specimen
increased by the increasing of cementing agent. The influence of moisture content is very important.
Tanaman membutuhkan CO2 untuk pertumbuhannya. Peningkatan konsentrasi CO2 di atmosfir akan
merangsang proses fotosintesis, meningkatkan pertumbuhan tanaman dan produktivitas pertanian
tanpa diikuti oleh peningkatan kebutuhan air (transpirasi).
Sebaliknya, kenaikan suhu di permukaan bumi mempunyai pengaruh yang "kurang menguntungkan"
terhadap pertanian, dapat mengurangi bahkan menghilangkan pengaruh positif dari kenaikan CO2.
Tulisan ini merupakan ulasan singkat untuk mengupas hubungan antara kenaikan CO2 dan suhu
dengan reaksi yang diberikan tanaman. Pembahasan dititikberatkan pada tingkat daun dengan
beberapa contoh-contoh hasil penelitian penulis. Dibahas juga mengenai perbedaan reaksi antara
tanaman C3 dan C4 ; perlunya "modelling" untuk memperkirakan hasil pada skala besar dan
kompleksnya sistem yang dihadapi.
Brown and Levinson's (1978) discussion on linguistic politeness has been used by some scholars (cf.
Adegbija, 1989 , Rhodes, 1989) as a basis of their analysis on politeness strategies in some languages
such as in Ogori, Yoruba, and Ojibwa. Two main types of politeness have been proposed by Brown
and Levinson, which are, positive and negative politeness. Positive politeness is the one which is used
to satisfy the speaker's needs of approval and belonging, whereas, negative politeness is the one
which has the main goal of minimising of a face-threatening act (Brown and Levinson, 1978:134).
