Early Maastrichtian larger foraminifera of the Qahlah Formation, United Arab Emirates and Sultanate of Oman border region

The Early Maastrichtian (Late Cretaceous) Qahlah Formation is the oldest stratigraphical unit lying upon the eroded top of the obducted Semail Ophiolite, of Santonian–Campanian age, in the Northern Oman Mountains. It crops out as a series of low hills on the western flank of the mountains, which are located along the boundary between the United Arab Emirates and the Sultanate of Oman. This paper presents the results of an investigation into the bio- and lithofacies of the Qahlah Formation in the Jabal Huwayyah section (at the boundary between the Al Ain area of the United Arab Emirates and the Buraimi area of Oman). The data collected were used to determine the age and depositional environment of the rock unit studied. In addition, the section is lithostratigraphically correlated with other sections in the study area. Microfossils from Jabal Huwayyah are represented mainly by the larger benthic foraminifera Loftusia elongata, L. morgani, Pseudorbitolina marthae, Orbitoides media, Omphalocyclus macroporus and Lepidorbitoides minor. These foraminifera are reported for the first time from this section. The diversity and abundance of fauna, particularly within the calcareous siltstone bed near the top of the formation (unique to the Huwayyah area), reflect a shallow marine depositional environment.     

Failures of structures during the January 24, 2020, Sivrice (Elazığ) Earthquake in Turkey

Natural Hazards - On January 24, 2020, a severe earthquake of magnitude Mw 6.8 hit the Sivrice district of Elaz?? province at 20:55 (17:55 GMT) local time. This earthquake caused...     

Landscape features and potential heat hazard threat: a spatial–temporal analysis of two urban universities

Urban universities are a microcosm of urban built-up areas, such as cities, but with a much smaller scale of spatial resolution. Within universities, there are many types of landscape features exhibiting different heat absorption and transmission capacities. These landscape features generate spatial–temporal heat signatures, and the knowledge about landscape features and urban heat hazard on university campuses is limited. The objective of this research is an assessment of landscape features and the potential heat hazard threats of two urban universities in ASEAN, located in the centre of the equatorial region. The focus of this research is on urban heat hazards in two urban universities in ASEAN, the University of Malaysia in Kuala Lumpur and the University of Indonesia in Jakarta, within the context of the spatial–temporal behaviour of urban heat and the urban heat effects on the environment and human well-being on campuses. The spatial and temporal analysis used to answer the objective of this research via data-gathering methods from image satellite, ground trough, and human perception study. The UM campus and UI campus, both urban campuses, had similar landscape features but had different total percentage areas of these features. The UM campus was 59.1% covered by the densely vegetated surface landscape feature, a percentage lower than that of the UI campus, which was 65.3% vegetation covered. The temporal results for the UHS of the UM campus in 2013–2016 show a maximum temperature of 39 °C. Therefore, the UHS of the UI campus demonstrated temporal behaviour in 2013–2016, with a maximum temperature of 38 °C. The UHS behaviour of the UM campus and UI campus had an air surface temperature with a maximum average temperature of 33 °C. The air surface temperatures exceeding 32 °C at the UM campus (12 pm until 6 pm?=?5 h) lasted for a longer time than those at the UI campus (12 pm until 3 pm?=?3 h). This study showed that, based on the perceptions on both campuses, if temperatures exceeded 30 °C, respondents were very hot and very uncomfortable, which will impact health and decrease work or academic achievements, as perceptions of heat intensity impact human well-being. Students perceived that heat intensity impacted their health and they reported becoming tired and lethargic under maximum temperatures and were very hot and very uncomfortable, and this condition impacted their work activity. These results indicated that, at both the UM and UI campuses, heat intensity impacts human well-being, with risks associated with hot temperatures. These two urban campuses are significant for ASEAN university awareness of the urban heat hazard of the equatorial area.     

Photocatalytic reduction of hexavalent chromium with commercial Fe/Ti oxide catalyst under UV and visible light irradiation

The photoreduction efficiency of toxic hexavalent chromium into non-toxic trivalent chromium was studied using local low-cost material and modern technology. The materials involved different iron–titanium oxide nanopowders synthesized via simple hydrothermal–hydrolysis process. X-ray diffraction and high-resolution transmission electron microscope were employed to study the structural properties of the as-prepared samples. The effects of molar ratio (Fe/Ti) and hydrothermal temperature on spectroscopic properties have been investigated using Fourier transform infrared FT-IR spectroscopy. The photocatalytic performance of hexavalent chromium was systematically studied at various conditions including initial concentration of Cr(VI), hydrothermal temperature and Fe/Ti ratios of mixed iron–titanium oxide powders. It has been found that the highest photoreduction efficiencies of Cr(VI) were 95.7 and 86.2% at initial concentrations 10 and 60 ppm of Cr(VI), respectively. The synthesized mixed Fe₂O₃–TiO₂ photocatalyst exhibited higher efficiency of about 88% under visible light irradiation. The as-prepared mixed oxide catalyst exhibited high photocatalytic conversion efficiency and recycling stability in comparison with different commercial catalysts.     

Deposition in a changing paleogulf: evidence from the Pliocene–Quaternary sedimentary succession of the Nile Delta,Egypt

Sedimentary complexes of ancient gulfs provide valuable information about paleoenvironmental dynamics. The study of several Pliocene–Pleistocene sections allowed reconstruction of the regional stratigraphical framework in the southwestern fringes of the Nile Delta. The Kafr El-Shiekh, the Gar El-Muluk, and the Kom El-Shelul formations of the Zanclean Age and the Wastani Formation of the Piacenzian Age constitute the Pliocene sedimentary succession in the study area. The establishment of 11 facies types related to 5 facies associations coupled with the results of the stratigraphical study indicate the existence of a paleogulf corresponding to the modern delta and lower valley of the Nile. This Nile Paleogulf appeared and reached its maximum spatial extent in the beginning of the Pliocene. Then, it retreated gradually and disappeared before the end of this epoch when alluvial sedimentation reestablished. There was significant flux of siliciclastic material to the study area. The Zanclean Flood in the Mediterranean Sea allowed marine incursion in the study area where the river valley incised during the precedent Messinian Salinity Crisis. Regional tectonic uplift and filling of the accommodation space with siliciclastic material from the eroded land were the main controls on the paleogulf evolution. Strengthened glaciation triggered global sea level fall, and alluvial deposition dominated the study area in the late Pliocene–Pleistocene.     

Assessment of lifetime cancer risk from natural radioactivity levels in Kadikoy and Uskudar District of Istanbul

The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K are measured in soil samples from various locations in the Kadikoy and Uskudar district of Istanbul (Turkey). The ²²⁶Ra activity concentrations range from 19.97 Bqkg^?1 to 50.80 Bqkg^?1 and average ²²⁶Ra concentration value 31.40 Bqkg^?1 was calculated. The ²³²Th activity concentrations range from 21.38 Bqkg^?1 to 52.61 Bqkg^?1 and average ²³²Th concentration value 34.44 Bqkg^?1 was calculated. The ⁴⁰K activity concentrations range from 464.06 Bqkg^?1 to 711.27 Bqkg^?1 and average ⁴⁰K concentration value 619.59 Bqkg^?1 was calculated. In addition, radium equivalent (Ra_eq), absorbed gamma dose rate (D), annual effective dose equivalent, (AEDE), excess lifetime cancer risk (ELCR) were calculated in this study. All of the calculations have been compared with both national and international standards and similar studies. As a result of this comparison, levels of natural radioactivity and radiological effects were slightly higher than the World average and Turkey.     

Experimental Effects of the Grass Shrimp, Palaemonetes pugio, on Hard-Substrate Communities in Chesapeake Bay and an Adjacent Coastal Bay, USA

With increased shoreline hardening and development, it is important to understand the ecological processes occurring in these and adjacent coastal habitats. A common species found associated with these hard-substrate habitats in Chesapeake Bay is the grass shrimp, Palaemonetes pugio. Caging experiments were conducted from June to August 2010 to examine the effects of shrimp on the recruitment and development of hard-substrate communities. Experiments were conducted at two low-salinity sites within Chesapeake Bay and one high-salinity site in an adjacent coastal bay in Virginia. The addition of grass shrimp reduced recruitment of polychaetes and scyphistomae of the sea nettle, Chrysaora quinquecirrha, and increased recruitment of encrusting bryozoans and the oyster, Crassostrea virginica. After 12?weeks, sea nettles at one low-salinity site, dominated predator-exclusion treatments. At the high-salinity site, oysters dominated when shrimp were present. Although it is unclear whether the results of short-term caging studies can be applied across larger temporal and spatial scales, the significant effects of grass shrimp on two important Chesapeake Bay species suggests that increases in hard-substrate habitat could have broader impacts within this and other systems.     

Assessment of advective–dispersive contaminant transport in heterogeneous aquifers using a meshless method

Groundwater solute transport phenomena typically occur in water-bearing zones with heterogeneous solute dispersive characteristics and/or media hydraulic properties. A radial basis function collocation method (RBFCM)-based numerical method was developed in order to investigate the ability of RBFCM to accurately portray solute transport phenomena under heterogeneous conditions. Simulations were performed for 1-D and 2-D transport scenarios in which scale-dependent dispersivity fields were taken into consideration and compared with available analytical solutions. Different radial basis functions (RBFs) were employed for assessing the sensitivity of the present method on the selected RBFs. The simulation results were also compared with the results of MT3DMS which is a modular three-dimensional transport model with alternative solution schemes including the method of characteristics, the implicit central finite difference and the third order total variation diminishing finite volume. The proposed model was also used to simulate a real case condition where solute transport through a two-layer soil medium had been investigated experimentally. The results showed that RBFCM represented a powerful tool for predicting the solute transport occurrence under heterogeneous conditions with high accuracy.