An inexpensive hand-operated device for cutting core liners

A simple hand-operated device for cutting longitudinal sections of core liners has been developed at a very low cost. The liner is placed on a stand and secured properly by circular plates and tightening levers. Two high-speed steel blades situated in diametrically opposite direction are pressed tightly on the liner. By rotating a handle these blades move to cut both sides of the liner simultaneously.

For cross-sectioning the core liner another simple hand-operated instrument has been illustrated. The liner is fixed in a stationary ring by tightening screws. An adjustable lever with a high-speed steel blade is fixed on a tool holder and welded to an outer ring which is rotated 180° by a handle to cut the liner. The cut portions are smooth, perfect and straight and the operation is very simple and safe.     

Calcareous Sands from a Coral Atoll-Should It Be Mined or Not?

Many lagoons of coral atolls contain huge reserves of very pure calcareous sands in an easily exploitable form that can be used in a number of industries. It is well known that the geomorphic situation in these coral islands is very delicate. With reference to the calcareous sand deposits in the coral atolls of Lakshadweep, a diversity of opinion exists on the aspect of exploitation, though the reserves were proved more than 20 years ago. Elsewhere calcareous sands have been used for several purposes. No raw materials other than coral sands and corals are available in these islands for developmental work such as construction of building and jetties. Several recommendations have been made to keep the system undisturbed to maintain the ecosystem. It is suggested that an attempt should be made to determine an optimum depth of exploitation of these sands without affecting the reef growth and balance of the ecosystem. This will improve the island economy and better quality of life for the islanders. The strategy will help development elsewhere also.     

Beach erosion and acceretion—An example from Kerala,Southwest Coast of India

The thickly populated coastal zone of Kerala, India is facing severe problems due to attack of high waves during the southwest monsoon. Systematic beach profiling at 5-km intervals was carried out along the 560-km stretch of the Kerala coast during the pre-and postmonsoon seasons in 1984. Beach volume changes were calculated at each profile station, and the erosional and accretional trends for the entire coastal tract were demarcated in a map. Total erosion along 55 stations is 1276 m³/m. The general erosional and acceretional trends were also found to coincide with diverging and converging littoral currents deduced from the wave refraction diagrams. Such study at periodic intervals will be highly useful for proper management of the coastal zone.     

On disturbances in a visco-elastic medium of Maxwell type in contact with a liquid medium and subjected to a magnetic field

Summary The problem of disturbances in a visco-elastic medium due to Maxwell in contact with a liquid medium — both being perfectly conductive — has been investigated when an impulsive force acts along the plane of the contact. The electro-magnetic equations of Maxwell, equation of elasticity and the stress-strain relations of the material have been used in the investigation.     

An analysis of problems related to dredging in a coral atoll: Kavaratti,Lakshadweep, Indian Ocean

Detailed survey on various aspects has indicated the presence of calcareous sands in the lagoons of Lakshadweep (Arabian Sea) suitable for a number of industries. No data are available about the effect of mining the deposits on these atolls. This paper attempts to analyze the data collected in studying the channel that has been dredged in connection with development of the harbor at Kavaratti lagoon Maximum depth in the lagoon is 3 m Outside the depth increases rapidly within a short distance of about 100 m Sediment in the lagoon is derived from the destruction of the reefs and consists of corals, halimeda, molluscan shells, foraminifers, and red algae Presently sands are being dredged from the lagoon and dumped in the sea and these sands are lost as there is a steep slope outside A study of shoreline records for the beaches adjacent to the dredging site shows that the shoreline is an area of accretion. It is quite possible that removal of 1 or 2 meters of sands from the lagoon floor will not affect the equilibrium if the reef is not disturbed Dredging of coral sands for different purposes is known from Fiji, Johnson Island, offshore Apia and no adverse effect has been noticed Removal of limited quantity of sands is recommended, since in a closed system of such atolls like Kavaratti there is always a surplus of sediment transported to the deep sea. The surplus sediment opens the way to sediment dredging. However, reef areas should not be disturbed since the reef is the most important sediment-generating site Studies on growth rate, currents, tides, and bathymetry should be continued to detect the adverse effect simultaneously with dredging The views expressed in this paper are entirely those of the author and no organization is responsible for them.     

Chemical evolution coefficients for the study of galactic evolution

A new evaluation of chemical evolution coefficients has been made using recent stellar evolution and nucleosynthesis data. The role of the low and intermediate mass stars in galactic nucleosynthesis has been emphasized. A significant amount of⁴He,¹²C and neutron-rich species is found to be contributed by these stars. Comparison with observed abundances suggests a primary origin of¹⁴N. The simple model of galactic evolution with the new coefficients has been used to derive the ratio of helium to heavy element enrichment in the Galaxy. The new stellar evolution data do not explain the large value of this ratio that has been determined observationally.     

On the deformations in a general linear substance of a layered media subjected to a body force and a deforming magnetic field

Summary The propagation of disturbances has been studied in a layered media, comprising a liquid and a general linear substance, subject to a body force and permeated by an initial magnetic field acting normal to the plane of the contact. The effect of the body force due to some internal source has been considered in the problem and a set of results has been obtained under two possible extreme variants of the boundary conditions in the form of integral forms, which can be computed to visualize the displacement—time and displacement—depth variations, both in the presence and absence of the body force. The effect of body force on the substance has been, as a sample case, illustrated in the graphs. The stress-strain relation of the general linear substance and the electromagnetic equations of Maxwell have been used in working out the problem.     

Surface flux modelling using ARIMA technique in humid subtropical monsoon area

In this paper, we attempt to fit sensible heat fluxes obtained by the profile method between 1–2 and 1–4 m height into the autoregressive integrated moving average (ARIMA) family. In both the profiles, fluxes are found to fit into the first-order autoregression [AR (1)] model, which is the continuous analog of the first-order Markov chain. The ARIMA (1, 0, 0) model was able to simulate the heat flux value for 1 h in advance for both the profiles (1–2 and 1–4 m height) generating a prediction error of 18.28% and 4.95%, respectively.     

Land scarcity and land access in a hazard-prone island: Sagar,Indian Sundarbans

The analytical inseparability of natural environment and society is reiterated by the findings of this study which contributes to a genre of studies that centre-stages the socio-ecological system. This study seeks to understand the interplay of state-related and other modes of securing property rights in the context of pervasive coastal hazards through a case study from the Indian Sundarbans region (Sagar Island in West Bengal). This paper also contributes to research pertaining to slow-onset disasters and attempts to examine emerging dimensions of land scarcity as well as diverse modes of access to land in the context of progressive ecological vulnerability. The analysis highlights the varying shades of declining land access and investigates how existing land policies and disaster management mechanisms remain far from extending security to communities experiencing environmental crisis. The paper thereby examines how community and state agencies adopting means to allocate property may in fact refute legality and perpetuate informality.