Observed Trends in Extreme Temperature over the Klang Valley,Malaysia

This study investigates the recent extreme temperature trends across 19 stations in the Klang Valley, Malaysia, over the period 2006-16. Fourteen extreme index trends were analyzed using the Mann-Kendall non-parametric test, with Sen’s slope as a magnitude estimator. Generally, the annual daily mean temperature, daily mean maximum temperature, and daily mean minimum temperature in the Klang Valley increased significantly, by 0.07°C yr~(-1), 0.07°C yr~(-1)and 0.08°C yr~(-1),respectively. For the warm temperature indices, the results indicated a significant upward trend for the annual maximum of maximum temperature, by 0.09°C yr~(-1), and the annual maximum of minimum temperature, by 0.11°C yr~(-1). The results for the total number of warm days and warm nights showed significant increasing trends of 5.02 d yr~(-1)and 6.92 d yr~(-1),respectively. For the cold temperature indices, there were upward trends for the annual minimum of maximum temperature,by 0.09°C yr~(-1), and the annual minimum of minimum temperature, by 0.03°C yr~(-1), concurrent with the decreases in the total number cold days (TX10P), with-3.80 d yr~(-1), and cold nights (TN10P), with-4.33 d yr~(-1). The 34°C and 37°C summer days results showed significant upward trends of 4.10 d yr~(-1) and 0.25 d yr~(-1), respectively. Overall, these findings showed upward warming trends in the Klang Valley, with the minimum temperature rate increasing more than that of the maximum temperature, especially in urban areas.     

Re‐examining green revolution diffusion and factor/input markets in Bangladesh after market liberalization

This paper re‐examines the effect of green revolution (GR) diffusion on factor/inputs demand in Bangladesh using an empirical model that allows for simultaneous determination of factors influencing adoption of GR technology at the current mature stage, as well as access to irrigation. Results reveal some alignments with conventional wisdom as well as few surprises. For example, while an increased demand for major inputs is expected, an increased demand for organic manure is an unexpected positive outcome. The GR adoption rate is significantly higher in villages with access to irrigation and fertile soils and, surprisingly, in infrastructurally underdeveloped villages. Together with other expected findings of GR technology uptake with higher cereal prices and irrigation use encouraged by access to credit, tenurial status and fertile soils, our findings suggest that investment in irrigation and soil conservation, as well as implementing measures to improve cereal prices and provide agricultural credit, could boost GR technology adoption.     

“Shock event”, an impact phenomenon observed in water wells around the Arabian Gulf coastal city Dammam,Saudi Arabia: possible relationship with Sumatra tsunami event of December 26, 2004

A sudden disturbance in water level was recorded by hydrographs monitoring wells in the coastal city Dammam, Saudi Arabia on December 26, 2004. The water level was being recorded from the shallow (1–3 M deep) coastal aquifer at that time. In two wells, this disturbance was observed ~12 h after the Sumatra earthquake/tsunami event of December 26, 2004. The timing of this event is synchronous in two wells near the coast, but an inland well away from the coast line did not show any such disturbance. It is hypothesized that this disturbance, we call it the “shock event”, is resulted by sudden impact of tsunamis traveling in the Arabian Gulf from southeast toward northwest. As the tsunamis propagated, they suddenly impacted the coastal shallow groundwater aquifer resulting in the “shock event”.     

Hydrological processes of adsorption,sedimentation, and infiltration into the lake bed during the 2004 urban flood in Dhaka city,Bangladesh

The urban flood of Dhaka city in September 2004 is a result of heavy rainfall (341 mm a day or more than 600 mm in 5 days). In addition to the local rainfall, elevated water levels in the surrounding rivers may have affected the flood duration by bank filtration. Two lakes, Banani and Gulshan, in the mid of the city are the part of general storm water retention system in Dhaka. Flood water runs through the lakes acting as channels to the pumping station downstream. A tank model is used in this study to describe the total drainage process with the hydraulic geometry and resistance laws to derive cross-sections and friction factors of the quasi-uniform flows. Assuming the dissolved matters of the flood water was of similar composition as in the lake sediments, the process was a combination of adsorption and sedimentation. Lake sediment samples collected in March 2004 show an anomaly of chromium which may reflect the previous 1998 flood, and there may be a diffusive leakage from the source area to the adjacent zones. Further evidence of infiltration process is seen in records of diurnal thermal stratification of Lake Banani. It responds to only heavy rainfalls over 100 mm/day, and the fact means that infiltration to the groundwater is rather intermittent.     

TEST OF RECIPROCITY AND SUPERPOSITION IN TIME DOMAIN INDUCED POLARIZATION MEASUREMENTS*

The principles of reciprocity and superposition, which hold in normal resistivity measurements, are sometimes considered to apply also to Induced Polarisation measurements. In this paper, an account is given of experiments designed to test how far such a proposition is justified. The experiments comprise a limited field test and more extensive observations using a tank analogue. Within acceptable limits, both tests showed that these basic theorems are applicable to I.P. potentials provided that these are measured at the same instant after switch off and that identical charging regimes are used. The implications of these findings are discussed.     

The crustal dynamics and the tectonic trends in the Bengal Basin

Seismological data of the events that took place in the Bengal Basin during 1918 to 1989 have revealed an increased frequency of earthquakes in the last 30 years. The increase in seismic activity is an indication of fresh tectonic activity or propagation of fractures from the adjacent seismic zones.The tectonic trend TT3 as determined from the tectonic flux and from the crustal model is in good coincidence with the NE-SW trending linear zone of gravity high, the zone of Moho upwarping and the location of earthquake events having fault-plane solutions of prominent strike-slip component. It is further observed that most of the earthquakes that occurred in the Bengal Basin in the 20th century follow the tectonic trend TT3. The NE-SW trending tectonic trend TT3 is inferred as one of the most remarkable features in the Bengal Basin. The extension of this trend is well marked by the “Halflong-Disang Thrust” in the NE and by the “Swatch of No-Ground” in the SW.The tectonic flux has also revealed some other striking tectonic trends distributed over broad regions and is not confined to definite geologic or physiographic provinces but instead is transverse to major structural elements of the region, thus forming conjugate sets of active zones. The focal mechanism solutions of 12 earthquake events reveal the nature of faulting which is predominantly strike-slip. The strike-slip fault solutions for most of the events are indicative of a changing pattern from convergence and subduction to strike-slip displacement in the Bengal Basin. The focal mechanism of two events having solutions of strike-slip with a normal fault component located on the tectonic trend TT3, the nature of Moho upwarping and the crustal configuration lend support to a process of crustal extension prevailing in the Bengal Basin. The crustal segment to the east of TT3 is relatively more mobile than that of the crustal segment to the west. The general trend of compression (P-axis) is N57 °W in the Bengal Basin, while it is N40 °E in the Bay of Bengal. The oblique convergence of the crustal segments situated in the Bengal Basin and in the Bay of Bengal has been inferred.     

Geochemical Investigations of Stratabound Gunga Barite Deposits of Khuzdar (Balochistan), Pakistan

Abstract: The Gunga barite deposits occur in carbonate clastic marine sequence of Jurassic age. These rocks are widely spread in Khuzdar-Lasbela belt which host important stratabound barite and zinc-lead deposits of Pakistan. These rocks are intricately folded and extensively faulted. The Gunga are low temperature hydrothermal deposits occurring as a series of disconnected lenses a few meters thick. Two mineralized horizons are recognized: barite in the upper zone, sphalerite and galena in the lower zone. Four types of barite mineralization occurs in Gunga stratabound replacement associated with 1) fracture filling, 2) open space fillings in solution collapsed breccia, 3) replacement in fault, and 4) veinlets associated with all these three types. The wall rocks of the Gunga deposits have also been altered by silicification, leaching and ferruginization.
The sulfur isotope values of most of the Gunga barite samples range from 23.8 to 27.8 per mil with an average of 26.4 per mil, which is very close to the average of isotopic values of epigenetic carbonate hosted Late Paleozoic Missouri barite deposits. The Gunga like other barite and sulfide deposits of Khuzdar-Lasbela belt are Mississippi Valley type, stratabound and of replacement origin precipitated from connate brines expelled during the incipient rifting of India from Gondwana land in the Late Jurassic and Early Cretaceous periods. The low content of copper, lead and zinc in the Gunga barite deposits suggests that these deposits were not formed in proximity to an igneous source of the ore solution.
The Gunga deposits are epigenetic and stratabound as their mineralization is structure controlled. There is an evidence of transgressive nature of host rock and wall rock alteration which are absent in stratiform or bedded deposits.     

Water quality parameters along rivers

Water samples have been collected from a part of Surma River along different points and analyzed for various water quality parameters during dry and monsoon periods. Effects of industrial wastes, municipal sewage, and agricultural runoff on river water quality have been investigated. The study was conducted within the Chattak to Sunamganj portion of Surma River, which is significant due to the presence of two major industries-a paper mill and a cement factory. The other significant feature is the conveyors that travel from India to Chattak. This study involves determination of physical, biological and chemical parameters of surface water at different points. The river was found to be highly turbid in the monsoon season. But BOD and fecal coliform concentration was found higher in the dry season. The water was found slightly acidic. The mean values of parameters were Conductivity 84–805μs; DO: dry- 5.52 mg/L, monsoon-5.72 mg/L; BOD: dry-1 mg/L, monsoon-0.878 mg/L; Total Solid: dry-149.4 mg/L, monsoon- 145.7 mg/L. A model study was also conducted and values of different model parameters were estimated.     

Temperature distribution in the transition region and inner corona

The energy balance equation for a general solar atmosphere without assuming the plane-parallel approximation is solved analytically. This leads to models for both the transition region and inner corona as well as for the outer corona. The form of the latter is very similar to that of the hydrostatic conduction model of Chapman (1957). However, in this paper we confine ourselves only to the former.Model I is electron-pressure dependent but model II depends particularly on the maximum coronal temperature T _m and its corresponding altitude h _m. Both the models are compared with recently constructed temperature models of Chiuderi and Riani (1974), McWhirter et al. (1975), and Gabriel (1976a). It is concluded that our model II reproduces these models within a factor of not more than 2.     

Efficacy of Hollow‐Fiber Ultrafiltration for Microbial Sampling in Groundwater

The goal of this study was to test hollow‐fiber ultrafiltration as a method for concentrating in situ bacteria and viruses in groundwater samples. Water samples from nine wells tapping a shallow sandy aquifer in a densely populated village in Bangladesh were reduced in volume approximately 400‐fold using ultrafiltration. Culture‐based assays for total coliforms and Escherichia coli, as well as molecular‐based assays for E. coli, Bacteroides, and adenovirus, were used as microbial markers before and after ultrafiltration to evaluate performance. Ultrafiltration increased the concentration of the microbial markers in 99% of cases. However, concentration factors (CF = post‐filtration concentration/pre‐filtration concentration) for each marker calculated from geometric means ranged from 52 to 1018 compared to the expected value of 400. The efficiency was difficult to quantify because concentrations of some of the markers, especially E. coli and total coliforms, in the well water (WW) collected before ultrafiltration varied by several orders of magnitude during the period of sampling. The potential influence of colloidal iron oxide precipitates in the groundwater was tested by adding EDTA to the pre‐filtration water in half of the samples to prevent the formation of precipitates. The use of EDTA had no significant effect on the measurement of culturable or molecular markers across the 0.5 to 10 mg/L range of dissolved Fe²⁺ concentrations observed in the groundwater, indicating that colloidal iron did not hinder or enhance recovery or detection of the microbial markers. Ultrafiltration appears to be effective for concentrating microorganisms in environmental water samples, but additional research is needed to quantify losses during filtration.