Seasonal variation of volatile organic iodine compounds in the water column of Funka Bay,Hokkaido, Japan

Volatile organic iodine compounds (VOIs) emitted from the ocean surface to the air play an important role in atmospheric chemistry. Shipboard observations were conducted in Funka Bay, Hokkaido, Japan, bimonthly or monthly from March 2012 to December 2014, to elucidate the seasonal variations of VOI concentrations in seawater and their sea-to-air iodine fluxes. The bay water exchanges with the open ocean water of the North Pacific twice a year (early spring and autumn). Vertical profiles of CH₂I₂, CH₂ClI, CH₃I, and C₂H₅I concentrations in the bay water were measured bimonthly or monthly within an identified water mass. The VOI concentrations began to increase after early April at the end of the diatom spring bloom, and represented substantial peaks in June or July. The temporal variation of the C₂H₅I profile, which showed a distinct peak in the bottom layer from April to July, was similar to the PO₄ ^3? variation profile. Correlation between C₂H₅I and PO₄ ^3? concentrations (r = 0.93) suggests that C₂H₅I production was associated with degradation of organic matter deposited on the bottom after the spring bloom. CH₂I₂ and CH₂ClI concentrations increased substantially in the surface and subsurface layers (0–60 m) in June or July resulted in a clear seasonal variation of the sea-to-air iodine flux of the VOIs (high in summer or autumn and low in spring).     

An objective analysis of the relationship between quality of life and socio-economic characteristics in Kumasi,Ghana

Increasing urbanisation and the growth of urban areas in cities in developing countries present major challenges for local governments, policy makers and urban planners even though the phenomenon offers opportunities. Studies focusing on the quality of life (QoL) help in assessing objectively, urban conditions which inform urban policy and planning. Using Kumasi as a case study, this paper investigates the relationship between quality of life and socio-economic characteristics such as gender, age, marital status, educational background, household income and housing type. To this end, the paper uses data from 500 households to examine the relationship between urban dwellers socio-economic characteristics and quality of life index in Kumasi. Findings indicated that objective QoL varied considerably with some of the socio-economic variables (household income and housing type) in the study area and these variables contributed significantly to the objective quality of life in Kumasi. The paper concludes that there are six (6) dimension of quality of life in Kumasi.     

Geomorphological and sedimentological comparison of fluvial terraces and karst caves in Zhangjiajie,northwest Hunan,China: an archive of sandstone landform development

The Zhangjiajie Sandstone Peak Forest Geopark (Zhangjiajie World Geopark) of northwest Hunan, China hosts a well-preserved sequence of fluvial terraces and karst caves. In this contribution, a comparative study of fluvial terraces with karst caves along the middle-lower Suoxi River in Zhangjiajie World Geopark is presented to improve the understanding of the development of striking sandstone landscape in the upper Suoxi River. By integrating geomorphological, sedimentological, and geochronological techniques, the possible correlation between fluvial terraces and karst caves, as well as their climatic and tectonic implications is investigated. The available electron spin resonance and thermo-luminescence numerical ages coupled with morphostratigraphic analysis indicate that aggradation of fluvial terrace levels occurred at ca. 347 ± 34 ka (T₄), 104.45 ± 8.88 to 117.62 ± 9.99 ka (T₃), 60.95 ± 5.18 ka (T₂), and Holocene (T₁), followed by the stream incision. Fluvial terrace levels (T₄ to T₁) correlate morphologically with the karst cave levels (L₁ to L₄), yet the proposed chronology for the fluvial terrace levels is a bit later than the chronological data obtained from karst caves. In northwest Hunan, where a unique sandstone peak forest landscape was extensively developed, the fluvial terrace sequences as well as the cave systems are the important archives for studying the evolution of the sandstone landscape. The beginning of the sandstone landscape development must be earlier than the aggradation of the fluvial terrace T₄, allowing this unique landscape to occur in the Middle Pleistocene.     

Modeling a major source of economic resilience to disasters: recapturing lost production

Terrorist attacks and natural disasters have potentially severe economic consequences in terms of property damage and business interruption. However, experience from the September 11 World Trade Center attack and other disasters indicates that the economy has a great deal of resilience. This refers to the ability to dampen the maximum potential economic output (business interruption) loss. One of the most prominent sources of resilience is the ability of businesses to reschedule, or recapture, lost production after the event. Although there have been applications of a fixed parameter recapture factor for each of several aggregated sectors of the economy, there has been little formal analysis of this resilience action. This study offers a theoretic framework for analyzing production rescheduling. It distinguishes the major conditions influencing two aspects that have previously been neglected: (1) the maximum time span over which the rescheduling can take place and (2) the likely decline of the maximum recapture as the business interruption increases. We divide the relevant time path into two periods after recovery. One is a function of a recaptured output path after recovery to the status of normal production. The other is a function for the maximum recaptured production, based on the recaptured output path. The recaptured output path function is assumed to follow a normal distribution function, and hence, total recaptured output follows the cumulative normal distribution function over time after productive capacity is restored. Also, we develop a new cumulative normal distribution function for interruption time duration, which is symmetric with respect to the output axis. This recapture function has unknown parameters. Empirical data on the recaptured amounts following an actual disaster can be used to estimate the parameters of this function using simulation methods.     

A DEM-based evaluation of potential flood risk to enhance decision support system for safe evacuation

A practical, DEM-based practical method is proposed to enhance flood risk management in fluvial areas by quantifying relative risk as a function of vulnerability to inland and evacuation difficulty. Both measures are based mainly on the topography of the region, so the method does not require detailed data on the physical characteristics of the land. First, we use the deterministic 8-node method on a digital elevation map (DEM) to trace storm waterways. Second, we repeat the process on a reversed DEM to trace evacuation routes that avoid the waterways and zones dangerously close to the rivers. Finally, on the basis of such two flow lines of evacuee and storm water, we proposed the protocol to evaluate the flood risk at every point on the map taking into account both the minimum time required for floodwater to arrive and duration of an evacuation from that location. The time that must be allocated for safe evacuation is defined as the potential flood risk of evacuation (PFRE). The method is demonstrated on a fluvial area of the Kaki River in Nagaoka city, Japan. In addition, we illustrated the application of the PFRE map to divide the region into areas of greater or lesser evacuation urgency.     

Analysis of Circular Elastic Plate Resting on Pasternak Foundation by Strain Energy Approach

In this paper, an analytical expression for the deflection of a thin circular elastic plate resting on the Pasternak foundation is derived by adopting the strain energy approach. The parametric study is carried out to observe the location of the plate lift-off and the variation of the deflection profiles for comparing the variation pattern reported in the literature based on an approximate solution technique. It is found that the radial distance of the point of lift-off of the plate decreases with increase in the values of both the shear modulus and the modulus of subgrade reaction of the foundation soil; the reduction being more for their lower values. It is also observed that the variation in deflection of the plate at any radial distance due to change in soil subgrade conditions is significant for lower values of modulus of subgrade reaction.     

Assessment of deforestation,biodiversity loss and the associated factors: case study of Ijesa-Ekiti region of Southwestern Nigeria

Deforestation is driven by a variety of factors, and has resulted in land use changes that threaten biodiversity, water and energy resources. However, lack of reliable data and survey information in Nigeria has made the estimation of the effect of deforestation difficult to establish. Consequently, the extent and rate of deforestation are less well known. The study therefore, examined and analyzed the spatial and temporal patterns of deforestation over the period of 25 years (1978–2003); measured the rates, trends and explained the factors that determined deforestation in Ijesa-Ekiti region of southwestern Nigeria. The major sources of data for the study were satellites images. These were Landsat MSS 1978, with spatial resolution of 80 m, SPOT XS 1986, SPOT XS 1994, with 20 m spatial resolution and NigeriaSat_1 2003, with 32 m spatial resolution. To make them comparable, they were georeferenced to the same coordinates system, filtered, resampled and enhanced for visualization in a GIS environment. Furthermore, Ilesa, Ijebu-Ijesa, Efon-Alaaye, Iloko-Ijesa, Erin-Oke and Erin-Ijesa were identified and selected for ground truthing to validate the tonal values recorded in the images with the features on the ground. The result of ground truthing was combined with visual image interpretation as training sites for supervised classification. Focus Group Discussions were held with people who had lived in the area for over 20 years as a means of eliciting factors of deforestation and the effects on forest biodiversity. The results indicated forest loss of 53,469.23 ha over the period of 25 years at an annual deforestation rate of 7.21, 2.47, and 5.40% per year for 1978–1986, 1986–1994 and 1994–2003, respectively. FGDs with various categories of people in the bigger towns confirmed deforestation in the area and were due to illegal lumbering, intensive agricultural practices and growth of settlements resulted from increase in human population. FGDs also revealed extinction of many forest species in their communities. In conclusion, the study advanced our understanding on techniques of analyzing deforestation using geo-spatial technology. It also generated a synthesis of information on the rates of deforestation and its driving forces, which are a complex mix of anthropogenic factors, the chief of which has been the conversion of forest resources to agricultural land use.     

Probabilistic Methods Applied to Unsaturated Numerical Modeling

The numerical modeling of unsaturated soil processes is becoming more prevalent worldwide. Although numerical modeling is becoming increasingly accepted in geotechnical engineering practice, care must be exercised and improper modeling techniques and procedures must be avoided. Many issues such as nodal resolution and imperfect convergence can result in inaccurate solutions. Unfortunately, analyses of highly nonlinear unsaturated soil flow and slope stability models can significantly increase the modeling time required. As a result, there is a trend to reduce the number of model runs. Results are often presented to client as single model runs or simplistic sensitivity analysis. This paper presents methodologies for applying probabilistic methods to unsaturated soils seepage and slope stability analysis models. The focus is on the application of the alternative point estimate method to practical problems in such a way as to minimize the number of model runs. The demonstration of a successful application to a waste rock pile is presented.     

Carbonate cements in Miller field of the UK North Sea: a natural analog for mineral trapping in CO<Subscript>2</Subscript> geological storage

Miller field of the North Sea has had high concentrations of natural CO₂ for ~70 Ma. It is an ideal analog for the long-term fate of CO₂ during engineered storage, particularly for formation of carbonate minerals that permanently lock up CO₂ in solid form. The Brae Formation reservoir sandstone contains an unusually high quantity of calcite concretions; however, C and O stable isotopic signatures suggest that these are not related to the present-day CO₂ charge. Margins of the concretions are corroded, probably because of reduced pH due to CO₂ influx. Dispersed calcite cements are also present, some of which postdate the CO₂ charge and, therefore, are the products of mineral trapping. It is calculated that only a minority of the reservoired CO₂ in Miller (6–24%) has been sequestrated in carbonates, even after 70 Ma of CO₂ emplacement. Most of the CO₂ accumulation is dissolved in pore fluids. Therefore, in a reservoir similar to the Brae Formation, engineered CO₂ storage must rely on physical retention mechanisms because mineral trapping is both incomplete and slow.     

Interactions between basalts and oil source rocks in rift basins： CO2 generation

Basalts interbedded with oil source rocks are discovered frequently in rift basins of eastern China, where CO2 is found in reservoirs around or within basalts, for example in the Binnan reservoir of the Dongying Depression. In the reservoirs, CO2 with heavy carbon isotopic composition (δ13C>-10‰ PDB) is in most cases accounts for 40% of the total gas reserve, and is believed to have resulted from degassing of basaltic magma from the mantle. In their investigations of the Binnan reservoir, the authors suggested that the CO2 would result from interactions between the source rocks and basalts. As the source rocks around basalts are rich in carbonate minerals, volcanic minerals, transition metals and organic matter, during their burial history some of the transition metals were catalyzed on the thermal degradation of organic matter into hydrocarbons and on the decomposition of carbonate minerals into CO2, which was reproduced in thermal simulations of the source rocks with the transition metals (Ni and Co). This kind of CO2 accounts for 55%-85% of the total gas reserve generated in the process of thermal simulation, and its δ13C values range from -11‰- -7.2‰ PDB, which are very similar to those of CO2 found in the Binnan reservoir. The co-generation of CO2 and hydrocarbon gases makes it possible their accumulation together in one trap. In other words, if the CO2 resulted directly from degassing of basaltic magma or was derived from the mantle, it could not be accumulated with hydrocarbon gases because it came into the basin much earlier than hydrocarbon generation and much earlier than trap formation. Therefore, the source rocks around basalts generated hydrocarbons and CO2 simultaneously through catalysis of Co and Ni transition metals, which is useful for the explanation of co-accumulation of hydrocarbon gases and CO2 in rift basins in eastern China.