Geochemistry of microgranular enclaves in Aligoodarz Jurassic arc pluton, western Iran: implications for enclave generation by rapid crystallization of cogenetic granitoid magma

Microgranular enclaves are common in the Jurassic Aligoodarz granitoids of western Iran. Enclaves Enclosed in Granodiorite (EEG) and Enclaves Enclosed in Tonalite (EET) are different but they overlap their hosts on variation diagrams. The EEG is compositionally intermediate between tonalite and granodiorite. Mixing between tonalitic and granodioritic magmas and fractional crystallization are two models examined as the origin of the EEG. Field, textural, mineralogical and chemical observations suggest that chemical equilibration, common in magma mixing, was not attained between the EEG and its host. This, together with other observations does not support magma mixing as a mechanism for forming the EEG. Alternatively, excessive nucleation of biotite ± Fe-Ti-oxides ± amphibole by rapid cooling at borders of a shallow magma chamber and later fragmentation and dispersal by dynamic arc plutonism best explains the EEG. However, channeling of a new magma into the nearly solid tonalitic host explains formation of the EET.     

Causes and extent of environmental impacts of landslide hazard in the Himalayan region: a case study of Murree, Pakistan

Pakistan is located at the cross-roads of plate boundaries, experiencing multiple hazards of earthquake, flood, drought, water-logging, salinization and recurrent landslides. This paper examines the causes and environmental impacts of frequently occurring landslide hazards in the Murree area of Pakistan??s Himalayan region. These are wide ranging in nature and in terms of the damage that result. The area under research was divided into eight blocks and randomly data collected. It was observed that landslides mostly occur along the road network and disturbed slopes. Immature geology, a wide variation in climate and degradation of the natural resource-base were found to be some of the causal factors responsible for the landslide hazards. During the past three decades, rapid expansion of urban zones contributed to the changing vulnerability of the area. The analysis revealed that a large majority of the households (75%) in the area have been directly or indirectly affected by landslide hazards. Damages to already scarce agricultural land, infrastructure and other properties are each year a regular and escalating phenomenon. Landslide size, frequency and consequent costs of damage have increased considerably.     

Assessment of the Design of an Experimental Cover with Capillary Barrier Effect Using 4 Years of Field Data

One important step in the design of inclined covers with capillary barrier effect (CCBE) is the determination of the water diversion length (DL). Numerical simulations can predict the DL more precisely than steady-state analytical solutions. Nevertheless, as simplified methods have always been part of engineering design, the application of analytical solutions with conservative boundary conditions, may allow engineers to make reasonable predictions, particularly during the pre-feasibility stage of a project. In this study, a CCBE was designed, constructed and instrumented at the Saint-Tite-des-Caps landfill, Quebec, Canada. This CCBE included a seepage control layer superimposing a sand-gravel capillary barrier. The seepage control layer was made up of deinking by-products (DBP), an industrial by-product that was previously disposed of as waste. The capillary barrier was designed using an adaptation of the Ross analytical solution and the scenario considered was that of steady-state flow during constant seepage flow applied uniformly at the top of the sand-gravel capillary barrier. Although these conditions appear simplistic, they were deemed reasonable because placement of the seepage control layer on the top of the capillary barrier led to very low suctions at the interface, thereby allowing uniform downward seepage rates, limited by the saturated hydraulic conductivity of the DBP. In this paper, a discussion about the behaviour of the cover system based on 4 years of field data from several instruments is presented. The challenge of using DBP, more precisely the settlement of the DBP layer and its impact on k _sat , is also assessed. The DL was reassessed considering the new k _sat . A discussion on the validity of employing analytical solutions to determine DL is also presented. This paper illustrates how certain variables affect the design of inclined CCBEs that include a highly compressible material as seepage control layer.     

Re-appraisal of earthquake catalog in the Pamir―Hindu Kush region,emphasizing the early and modern instrumental earthquake events

Journal of Seismology - The Pamir-Hindu Kush region is seismically the most dynamic and active zone that went through many devastating earthquakes. While much research is ongoing to produce seismic...     

Electrochemical Treatment of Dye Solution by Oxalate Catalyzed Photoelectro‐Fenton Process Using a Carbon Nanotube‐PTFE Cathode: Optimization by Central Composite Design

Decolorization of C.I. Basic Blue 3 (BB3) by oxalate catalyzed photoelectro‐Fenton process based on carbon nanotube‐polytetrafluoroethylene (CNT‐PTFE) electrode as cathode under visible light was studied. A comparison of electro‐Fenton, photoelectro‐Fenton, and photoelectro‐Fenton/oxalate processes for decolorization of the solution containing BB3 has been performed. The results showed that color removal follows the decreasing order: photoelectro‐Fenton/oxalate > photoelectro‐Fenton > electro‐Fenton. Response surface methodology (RSM) was employed to assess individual and interactive effects of the four main independent parameters on the decolorization efficiency. A central composite design (CCD) was employed for optimization of photoelectro‐Fenton/oxalate treatment of BB3. The analysis of variance (ANOVA) showed a high coefficient of determination value (R² = 0.958) and satisfactory prediction second‐order regression. This study clearly showed that RSM was one of the suitable methods to optimize the operating conditions.     

Closure to ＂Discussion on ＇Optimum placement and characteristics of velocity-dependent dampers under seismic excitation＇ by SA Mousavi and AK Ghorbani-Tanha＂ by Izuru Takewaki

The authors would like to thank the discusser for his considerations and comments. The discusser believes that some of the derived formulations need to be referred to his previously published works and also some related studies have not been cited.     

The measurement of gamma-emitting radionuclides in beach sand cores of coastal regions of Ramsar,Iran using HPGe detectors

Radionuclides which present in different beach sands are sources of external exposure that contribute to the total radiation exposure of human. ²²⁶Ra, ²³⁵U, ²³²Th, ⁴⁰K and ¹³⁷Cs analysis has been carried out in sand samples collected at six depth levels, from eight locations of the northern coast of Iran, Ramsar, using high-resolution gamma-ray spectroscopy. The average Specific activities of natural radionuclides viz., ²²⁶Ra, ²³⁵U, ²³²Th, ⁴⁰K and ¹³⁷Cs, in the 0–36 cm depth sand were found as: 19.2 ± 0.04, 2.67 ± 0.17, 17.9 ± 0.06, 337.5 ± 0.61 and 3.35 ± 0.12 Bq kg⁻¹, respectively. The effects of organic matter content and pH value of sand samples on the natural radionuclide levels were also investigated. Finally, the measured radionuclide concentrations in the Ramsar beach were compared with the world average values, as reported by UNSCEAR (2000). None of the studied beaches were considered as a radiological risk.     

Study of Danjon limit in moon crescent sighting

About 70 years ago “André Danjon” a French astrophysicist showed that as elongation of the moon decreases the arc length of crescent gets less too. By studying the recent observational data, he concluded that at 7 degree elongation, the length of arc (cusp to cusp) will reach zero degree. Today, this value is named as Danjon limit, which points to the limit at which the moon crescent is formed. Danjon believed that the effective factor for occurring this limit was the shadows of moon’s mountains. Later researchers have obtained different values for this limit. In this research based on the new data, the decreasing dependence of length of arc versus elongation was obtained. The results show that the Danjon limit is about 5 degrees. The effective factors to form the Danjon limit are then given and discussed. By considering the effects of astronomical seeing and shadows of lunar features, the values of the arc length were calculated and compared with the observational data curve. The results of this study show good agreement with the observational data. The present research shows that the above-mentioned effects can reduce the length of arc. The effect of libration and roughness of the lunar terrain of the moon in forming the moon crescent were also considered, and the possibility of observing thinner crescents by photometric model and breaking the Danjon limit were given.