the cycloalkylation of diethyl malonate and ethyl cyanoacetate with alkyl dihalide was investigated by using comminuted potassium carbonate as a base and toluene as a solvent in the presence of hexadecyltrimethylammonium bromide (htmab) as a phase-transfer catalyst, which provided a conventional procedure with the advantage of short reaction period and high product yield. the factors influencin...

abstract a study was conducted to evaluate the effect of incubation time, sewage sludge and clay content on the distribution of nickel and cadmium in different fractions of selected calcareous soils. to meet this purpose, an experiment with two different soils (4 and 30 percent caco3), two different textures (8 and 40 percent clay), two levels of nickel (0 and 100 mg.kg-1), two levels of cadmiu...

the gulf of mannar, located between india and sri lanka, is a shallow embayment of the bay of bengal. the gulf, which has been declared a bio-reserve is a highly productive area endowed with rich marine fauna including corals. in order to study the origin and nature of the sediments and paleo-environment, 2.6 m length core was collected with 5cm interval at 1320m water depths. textural studies ...

the transport properties of liquids and gases through polymeric materialsplay a very important role in some areas of industrial applications. in thisstudy, natural rubber (nr)/caco3 composites were prepared by melt mixingmethod. by equilibrium swelling test, the transport process of toluene in the prepared natural rubber composites was investigated. the diffusion and transport of toluene throug...

Metal porous foams have been eliciting much interest in recent years due to their high capacity of energy absorption. The characteristics of the pores in these materials play an important role on their energy absorption capability and other properties. This study reports the fabrication of aluminum closed-cell foams by accumulative roll-bonding (ARB) technique using calcium carbonate (CaCO3) as...

droxide by calcium carbonate. The calcium carbonate dosage ranged from 3 to 6 g/day. They found that low-calcium dialysate induces a negative calcium balance during hemodialysis (HD) with a worsening of SHPTH and concluded that a change in the current policy of the treatment of renal osteodistrophy can be necessary to prevent these alterations. For 1 yr, we studied the effect oflow-calcium dial...

introduction: nowadays, due to mechanization of life, consumers need of food which they spent little time for preparation, so fresh cut industry is growing rapidly in the world. these products had strong growth since 1940, and in 2013, most sales of fresh cut fruit related to apples, against 21.8 percent. minimal processing operations include grading, washing, sorting, slicing, chopping and the...

Scleractinian coral skeletons are made mainly of calcium carbonate in the form of aragonite. The mineral deposition occurs in a biological confined environment, but it is still a theme of discussion to what extent the calcification occurs under biological or environmental control. Hence, the shape, size and organization of skeletal crystals from the cellular level through the colony architectur...

Quality of agriculture drain water was assessed from selected locations in Guntur district, Andhra Pradesh, India. Waste samples collected drains were analysed for quality parameters such as pH, electrical conductivity, total dissolved solids, hardness, chlorides, carbonates, bicarbonates, calcium, magnesium, sulphates, phosphates, sodium, potassium, ammonical nitrogen, nitrates oxygen and chem...

Polyamide-66(PA66)/CaCO3 micro- and nano-composites were prepared using a polymer solution method at filler loading of 0, 1, 2 and 3 weight percent. Nano-size of CaCO3 was synthesized by micro-emulsion technique. The material was characterized by XRD, SEM, FTIR and UV-VIS techniques. XRD results of composites suggested that CaCO3 particles are found in the amorphous phase of the semi-crystallin...