Lower Columns Research Articles

Source attribution of carbon monoxide and ozone over the Indian subcontinent using MOZART-4 chemistry transport model

Daily simulations of tropospheric carbon monoxide (CO) and ozone (O3) have been made using MOZART-4 (Model for OZone And Related chemical Tracers version 4) during 2007–08. The model simulated CO and O3 are evaluated against MOZAIC (Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft) airborne observations over Hyderabad and IASI (Infrared Atmospheric Sounding Interferometer) retrievals over five most populous cities of India i.e. Mumbai, Delhi, Bangalore, Hyderabad, and Ahmedabad. The MOZAIC tropospheric column showed winter maxima and summer minima for CO whereas spring maxima and summer minima for O3. These seasonal features are reproduced well by model over Hyderabad. Model lower and middle tropospheric CO (O3) columns are positively biased by about 14 (8) ppbv as compared to MOZAIC observations. Model underestimated (overestimated) IASI CO columns during pre-monsoon (post-monsoon) while it overestimated IASI O3 columns throughout the year. Model simulated column of CO and O3 are positively biased by 4–13% and 23–33% respectively as compared to the IASI retrievals over five most populous cities. Tagged and sensitivity simulations of MOZART-4 have been used to quantify the contribution of different sources to the tropospheric CO and O3 distribution over the Indian landmass region. At surface, anthropogenic contribution varies from 55% to 81% during different seasons with an annual average contribution of 67%. This contribution decreases with increasing altitude up to 35% at 300 hPa. The contribution of photochemically produced CO is found to be 9–33% at surface. Unlike ANT-CO, the photochemically produced CO increases with altitude as it reaches up to 48% at 300 hPa. Surface BB-CO contributes upto 30% over parts of North East India during pre-monsoon season. Contribution of NAT-CO is found to be negligible (Approximately 6%) near surface as well as at the higher altitudes. Sensitivity simulations are used to decompose the total ozone (TO) into contributions from enhancement of ozone from Indian anthropogenic emissions, referred as Indian pollution ozone (IPO) and from the total background ozone (TBO). Annual total ozone is found to be 30 to 70 ppbv at surface and 77 to 85 ppbv at 300 hPa over the Indian landmass region. IPO and TBO contribute annually 58% and 42% at surface while 45% and 55% at 300 hPa respectively. The IPO contributes strongly at surface, with maximum (68%) impact during pre-monsoon season.

Seismic performance of bolted connection of H-beam to HSS-column with web end-plate

This paper presents an experimental study on a bolted joint for connecting H-section steel beams to square hollow structural steel (HSS) columns and connecting upper and lower HSS columns in a multi-storey prefabricated steel structure. The components within a module are welded together in the factory, and the modules are assembled on site using high-strength bolts. A rigid connection or a semi-rigid connection can be achieved by adjusting the number and size of bolts. The stiffness of semi-rigid bolted connection changes with the load. The connection is rigid during minor and moderate earthquakes, whereas during major earthquakes, the cover plate slips relative to the beam flange to dissipate energy. In this paper, model tests and finite element analysis (FEA) of the seismic performance under cyclic loads are conducted on six full-scale connections, and the results are compared with the results of a welded connection. The failure mode, slip behaviour, variation and distribution of the bolt tensions, and seismic performance of the connections, including the hysteretic behaviour, skeleton curve, ductility, rotational capacity and stiffness degradation, are obtained. The influences of the number of bolts and the thickness of cover plate on the mechanical and seismic properties are studied. The results show that a reasonable larger bolt hole can facilitate the installation and improve the ductility and energy dissipation capability without significantly affecting the load-carrying capacity of the connection. The results show that the proposed bolted connection has good hysteresis behaviour, energy dissipation and ductility. It is suitable for earthquake-resistant structures.

Using a Speed-Dependent Voigt Line Shape to Retrieve O2 from Total Carbon Column Observing Network Solar Spectra to Improve Measurements of XCO2.

High-resolution, laboratory, absorption spectra of the oxygen (O2) band measured using cavity ring-down spectroscopy were fitted using the Voigt and speed-dependent Voigt line shapes. We found that the speed-dependent Voigt line shape was better able to model the measured absorption coefficients than the Voigt line shape. We used these line shape models to calculate absorption coefficients to retrieve atmospheric total columns abundances of O2 from ground-based spectra from four Fourier transform spectrometers that are apart of the Total Carbon Column Observing Network (TCCON) Lower O2 total columns were retrieved with the speed-dependent Voigt line shape, and the difference between the total columns retrieved using the Voigt and speed-dependent Voigt line shapes increased as a function of solar zenith angle. Previous work has shown that carbon dioxide (CO2) total columns are better retrieved using a speed-dependent Voigt line shape with line mixing. The column-averaged dry-air mole fraction of CO2 (XCO2) was calculated using the ratio between the columns of CO2 and O2 retrieved (from the same spectra) with both line shapes from measurements made over a one-year period at the four sites. The inclusion of speed dependence in the O2 retrievals significantly reduces the airmass dependence of XCO2 and the bias between the TCCON measurements and calibrated integrated aircraft profile measurements was reduced from 1% to 0.4%. These results suggest that speed dependence should be included in the forward model when fitting near-infrared CO2 and O2 spectra to improve the accuracy of XCO2 measurements.

Exploratory study of adopting longitudinal column reinforcement details as a design-controllable tool to seismic behavior of exterior RC beam-column joints

This study presents the test results of seven exterior beam-column joints with different longitudinal reinforcement details for the columns. The test program included a beam-column joint designed to serve as a control specimen, in which column reinforcement was continuous ribbed steel bars. The other six specimens were divided into two groups, three specimens for each group. In the first group, the longitudinal column reinforcement was detailed with well-confined lap-splice longitudinal bars: two specimens were reinforced with lap-splice deformed steel bars and the later was with lap-splice plain steel bars. The same reinforcement details were used for the second group but additional longitudinal basalt fiber reinforced polymer (BFRP) rebars were placed at the joint and extended to the upper and lower columns. The test results showed that splicing the longitudinal column reinforcement successfully reduced the contribution of the joint to the deformability of the beam-column joint. Furthermore, adding BFRP rebars to the beam-column joint could be applied as damage controllable bars reducing both the damage level at the serviceability state and the shear deformability of the joint up to failure. A sole strut resistant mechanism was realized by the joints of all test specimens detailed with lap-spliced longitudinal column reinforcement. Ultimately, the test results point to a probability to the renunciation of the ACI 318-11 requirements for splicing longitudinal column reinforcement at column mid-height.

Absorber Model: the Halo-like model for the Lyman-α forest

We present a semi-analytic model for the Lyman-α forest that is inspired by the Halo Model. This model is built on the absorption line decomposition of the forest. Flux correlations are decomposed into those within each absorption line (the 1-absorber term) and those between separate lines (the 2-absorber term), treating the lines as biased tracers of the underlying matter fluctuations. While the nonlinear exponential mapping between optical depth and flux requires an infinite series of moments to calculate any statistic, we show that this series can be re-summed (truncating at the desired order in the linear matter overdensity). We focus on the z=2–3 line-of-sight power spectrum. Our model finds that 1-absorber term dominates the power on all scales, with most of its contribution coming from H I columns of 1014–1015 cm−2, while the smaller 2-absorber contribution comes from lower columns that trace overdensities of a few. The prominence of the 1-absorber correlations indicates that the line-of-sight power spectrum is shaped principally by the lines' number densities and their absorption profiles, with correlations between lines contributing to a lesser extent. We present intuitive formulae for the effective optical depth as well as the large-scale limits of 1-absorber and 2-absorber terms, which simplify to integrals over the H I column density distribution with different equivalent-width weightings. With minimalist models for the bias of absorption systems and their peculiar velocity broadening, our model predicts values for the density bias and velocity gradient bias that are consistent with those found in simulations.

INVESTIGATION OF STRONG COLUMN – WEAK BEAM RATIO IN MULTI-STOREY STRUCTURES

It is expected that the engineering constructions should carry the vertical and horizontal loads during the service within the determined safety margin. Basic principal of having strong column weak beam preference is essential for earthquake resistant structures for all construction types including concrete, steel, wood and prefabricated. The major criteria for having earthquake resistant structure is to ensure that the columns are stronger and carry the most load than the beam in the nodes. This criterion has been widely adopted in earthquake codes in Europe, USA, Japan and India. It is possible to absorb and consume the earthquake energy via beam plastic joint hinges if the columns are constructed to be more durable than the beams. For this, it is foreseen that the ratio of the ultimate strength of the upper and lower columns to the right and left beams (β) should be greater than one (β = 1.2) in the beam-column joints as stated in the Turkish Earthquake Code. This coefficient is usually greater than 1.2 in the earthquake codes adopted in the world. It was observed that many structures were damaged or collapsed due to not meeting the coefficient criteria stated above. This criterion is the most effective one among many to prevent the damage in the structure under seismic action. In this study, the effect of the change in the coefficient on the column and beam moments is investigated under the Turkish Earthquake Code. Different numerical examples are presents for the coefficient of 10. The results of the investigation highlighted that irregularity in the strong column weak beam composition may negatively affect the other irregularities in the structure.

Seismic performance of mixed column composed of square CFST column and circular RC column in Chinese archaized buildings

This paper presents some quasi-static tests for 4 mixed columns composed of CFST column and RC column. The seismic performance and failure mode were studied under low-cyclic revised loading. The failure mode was observed under different axial compression ratios. The hysteretic curve and skeleton curve were obtained. The effects of axial compression ratio on yield mechanism, displacement ductility, energy dissipation, stiffness and strength attenuation were analyzed. The results indicate that the failure behavior of CFST-RC mixed column with archaized style is mainly caused by bending failure and accompanied by some shear failure. The axial compression ratio performs a control function on the yielding order of the upper and lower columns. The yielding mechanism has a great influence on the ductility and energy dissipation capacity of specimens. Based on the experiment, finite element analysis was made to further research the seismic performance by ABAQUS software. The variable parameters were stiffness ratio of upper and lower columns, axial compression ratio, yielding strength of steel tube, concrete strength and rebar ratio. The simulation results show that with the increase of stiffness ratio of the upper and lower columns, the bearing capacity and ductility of specimens can correspondingly increase. As the axial compression ratio increases, the ductility of the specimen decreases gradually. The other three parameters both have positive effect on the bearing capacity but have negative effect on the ductility. The results can provide reference for the design and engineering application of mixed column consisted of CFST-RC in Chinese archaized buildings.

Beam–column subassemblies with construction joint in columns above and below the beam

Construction joints in columns are unavoidable in multi-storey reinforced-concrete structures. According to ACI 224.3R-95, construction joints in columns are to be provided below the beam for lower storey columns and above the floor slab for upper storey columns. A review of the literature reveals that little attempt has been made so far to study the effect of cyclic loading on beam–column subassemblies with construction joints in the column above and below the beam. In the present paper, one-third scaled beam–column joint specimens were designed as per relevant provisions of the Indian standard code of practice and detailed as per ductile detailing procedures. Flexural strength ratios of the specimens were 1·2, 1·4, 1·7 and 2·0. Specimens were cast in stages, providing construction joints in the column as per ACI 224.3R-95 to simulate in situ construction. It was observed that ductility, initial stiffness and energy dissipation capacity reduced by 30–44%, 16–19% and 53–64%, respectively, in specimens with double construction joints in the column compared to control specimens.

Using rigidity elements to strengthen one-storey buildings frames

The study focuses on strengthening industrial buildings frames by introducing rigidity elements. Materials concentration principle in rigidity elements in the form of reinforced concrete columns is used and the influence degree on a building frame operation is estimated. This changes the performance of the overlay disk as an element that distributes horizontal forces. The paper describes basic dependencies determining the correlation between rigidity characteristics of rigidity elements and ordinary columns. They are determined by reinforced concrete frame movements when the lower section columns moments reach limit values. In resulting exposure rigidity elements accept basic horizontal efforts, and ordinary columns work as centrally compressed. Calculation results are presented as graphs of force variation depending on correlation between rigidity characteristics of rigidity elements and ordinary columns. The paper outlines that after introducing rigidity elements they act as basic distributing horizontal loads element. The overlay disk has the final load bearing capacity and regulates the limit distances between rigidity elements. The introduction of rigidity elements into the building frame should be accompanied by appropriate measures to strengthen structure foundations. The research proves that this method of one-storey industrial buildings frames reinforcement enables to use materials and technologies during reconstruction more efficiently.

Bond strength between steel and self-compacting lower expansion concrete in composite columns

In order to study the bond behavior between the steel tube and the concrete infill, a total of 17 self-compacting lower expansion CFST columns were prepared and tested. Cross-sectional dimension, dosage of concrete expansive agent, concrete compressive strength, steel tube fabrication method and interface condition were varied to assess their effect on the ultimate average bond strength. The push-out load-slip curves for each specimen are obtained and the distribution of the interface bond stress along the member axial direction and around the cross-section for various load levels are reported. The test results indicate that the steel tube interface roughness, influenced by both the steel tube fabrication method and the interface condition, the maximum flat width-to-thickness ratio (D/t), the concrete compressive strength, and the dosage of expansion agent are the main influence factors for interface bond strength. Then, regression analysis was performed to examine the bond strength of the test results of 19 square and 13 rectangular CFST columns with cold-formed steel tubes from this investigation and other additional references. Considering the influences of the dosage of concrete expansion agent, concrete cube compressive strength and D/t ratio to the bond stress, two empirical equations have been proposed for predicting the ultimate average bond strength for square and rectangular self-compacting lower expansion CFST columns with cold-formed steel tube respectively. Finally, by the analysis of the test data and the previous four segments bond stress-slip curve model, a new bond strength-slip model fitting equation has been proposed to predict the bond stress development.

Experimental study of an innovative modular steel building connection

In modular steel building (MSB) built by unit-prefabricated on-site assembled construction method, connections are critical parts that can strongly influence the overall structural stability and robustness of the MSB. Previous MSB connections mainly use intermediate connecting plates, which may pose practical difficulties to certain modular arrangements or installations. Thus, this paper proposed an innovative MSB connection design with an intermediate plug-in device and a beam-to-beam bolt system as the horizontal and vertical connections, respectively. This connection design can ensure convenient installation, eliminating on-site welding. Two static uniaxial loading tests and four quasi-static cyclic loading tests were conducted on the T-shaped MSB connection to explore its load transfer capacity and aseismic behavior. Results showed that gaps would form between the upper and the lower columns because of its two-unit-joint structure. This gap can influence the deformation patterns and bending demand distributions in each unit joint. The weld quality in the unit joints was critical to ensure overall safety. Stiffeners can effectively strengthen the stiffness and load-bearing capacity. The deformation capacity of the connection was significantly influenced by the stiffness of floor beam–column joint and ceiling beam–column joint as well as the relative magnitudes between them.

The Analysis of High Dimensional Contingency Table with Interactions

This paper is focused on the analysis of categorical data in a 2 × c × K contingency table. The theoretical frame work of a 2 × c design is extended to 2 × c × K with provision for testing interactions among subsets of either lower or upper columns of the designated table. The developed chi square tests for the total interactions as well as for the partitions are shown to be significant and the degrees of freedom additive.

Fire response of exterior reinforced concrete beam-column subassemblages

Investigating the structural response of reinforced concrete beam-column sub-assemblies at elevated temperatures is the purpose of this paper. This goal was achieved by conducting the ISO-834 standard fire test on two identical one-third scaled reinforced concrete beam-column subassemblage test specimens. The test specimens, which each consisted of one reinforced concrete cantilever beam anchored at the mid-height of a reinforced concrete column, were installed together in a full scale furnace and subjected to downward and upward service loads, respectively. The fire compartment fully engulfed the cantilever beams (except the beams’ top face and the loading points), the beam-column connections and the lower columns. The fire test terminated after 74min as soon as the tensile longitudinal steel bars of the upward-loaded cantilever beam attained the predefined critical temperature 530°C. The lower columns exhibited partial concrete spalling and typical diagonal cracks appeared at the beam-column connections. Based on the recorded internal temperature distributions at the joint cores it was found that the material strength loss in the fire had insignificant impact on the load bearing mechanism of the joints. On the other hand, the gradual decrease in rotation capacity of the beam ends during the fire course considerably influenced the load-deflection relationship. A detailed numerical work has been carried out to simulate the response of the test specimens and will be published elsewhere.

Asynchronous modes of vibrations in linear conservative systems: an illustrative discussion of plane framed structures

The theme of asynchronous modes of vibration is recast in this paper to address the case of linear conservative discrete systems. In fact, it is known that linear non-conservative discrete systems such as those characterized by a non-symmetric stiffness matrix may undergo asynchronous free vibrations. Yet, non-conservativeness is not mandatory for the occurrence of asynchronous modes, as it is illustrated in this investigation of simple plane frames, provided the system parameters are properly chosen. Firstly, a one-storey-frame model, with consistent-mass and stiffness matrices, is studied and conditions for the occurrence of asynchronous modes are established. Next, a three-storey shear building is modelled, with lumped-mass matrix, and isolated asynchronous modes are not observed. However, non-isolated asynchronous modes are seen to exist, including a case in which the first floor is at rest. In this scenario, the upper floors play the role of vibration controllers, sparing the lower columns from oscillating. This might be welcome from the architectural viewpoint, so that pilotis would not be a priori ruled out in case of earthquake-borne vibration. Usually the participating masses of the asynchronous modes are low (and even null). To maximize the asynchronous-mode participating mass, a final model of the three-storey frame is discussed, this time taking into account the flexural stiffness of both the columns and the beams, although still using lumped-mass matrix. In this case, it is seen that much larger participating masses can be obtained for the asynchronous mode. Since asynchronous modes are associated with the vibration localization phenomenon, they can be potentially explored in the design of vibration controllers or, alternatively, energy harvesting systems.

High‐resolution NO2 observations from the Airborne Compact Atmospheric Mapper: Retrieval and validation

AbstractNitrogen dioxide (NO2) is a short‐lived atmospheric pollutant that serves as an air quality indicator and is itself a health concern. The Airborne Compact Atmospheric Mapper (ACAM) was flown on board the NASA UC‐12 aircraft during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality Maryland field campaign in July 2011. The instrument collected hyperspectral remote sensing measurements in the 304–910 nm range, allowing daytime observations of several tropospheric pollutants, including nitrogen dioxide (NO2), at an unprecedented spatial resolution of 1.5 × 1.1 km2. Retrievals of slant column abundance are based on the differential optical absorption spectroscopy method. For the air mass factor computations needed to convert these retrievals to vertical column abundance, we include high‐resolution information for the surface reflectivity by using bidirectional reflectance distribution function data from the Moderate Resolution Imaging Spectroradiometer. We use high‐resolution simulated vertical distributions of NO2 from the Community Multiscale Air Quality and Global Modeling Initiative models to account for the temporal variation in atmospheric NO2 to retrieve middle and lower tropospheric NO2 columns (NO2 below the aircraft). We compare NO2 derived from ACAM measurements with in situ observations from NASA's P‐3B research aircraft, total column observations from the ground‐based Pandora spectrometers, and tropospheric column observations from the space‐based Ozone Monitoring Instrument. The high‐resolution ACAM measurements not only give new insights into our understanding of atmospheric composition and chemistry through observation of subsampling variability in typical satellite and model resolutions, but they also provide opportunities for testing algorithm improvements for forthcoming geostationary air quality missions.

Reconstructing the Holocene depositional environments along the northern coast of Sfax (Tunisia): Mineralogical and sedimentological approaches

A sedimentological and mineralogical study of sedimentary cores allowed reconstructing the evolution of depositional environments along the Northern coast of Sfax (Tunisia). The aim of this research work is to identify the factors controlling the sedimentation from the Holocene to the Present time. Three 30-m sediment cores collected by drilling at 30 m water depth were analyzed for their color, magnetic susceptibility signal, grain size by laser diffraction, organic matter content by loss of ignition, carbonate content by calcimetry and mineralogy by X-ray diffraction on bulk powder and clay <2 μm. They broadly present the same sedimentological and mineralogical features. Microscopical observations of petrographic slides allowed identifying six main sedimentary facies. Bulk mineralogical assemblages comprised clay minerals, quartz, calcite, gypsum and K-feldspars were examined. Considerable change was observed in the carbonate content that mimicked the bioclaste abundance and diluted the detrital minerals (clay minerals, quartz and feldspars). The gypsum mainly occurred in the lower sedimentary columns (SC12 and SC9) and in the upper/middle of core SC6. The clay fraction was made of a mixture of kaolinite, illite, smectite and palygorskite with no clear variation through core depth. Both grain-size parameters and magnetic susceptibility profile showed a sharp transition in the upper 2–5 m of the sedimentological columns. Coarse, sandy to gravely sediments characterized by a low magnetic susceptibility signal were replaced by fine bioclastic-rich clayey sediments. The analysis of vertical succession of depositional facies revealed a fluvial depositional environment (coastal plain) basically marked by fluvial channels and inundation plains at the bottom of all cores. However, core-top sediments recorded a littoral marine environment with sand depositions rich in gastropods, lamellibranches and algæ. Depositional facies, sedimentological and mineralogical parameters were consistent with a transition from a fluviatile depositional environment with some emersion phases marked by the gypsum precipitation, to a marine littoral environment. Such evolution was accompanied with a relative sea-level rise which flooded the fluvial system at the coastal plain during the Holocene, in agreement with sea-level fluctuations in southeast Tunisia during the Holocene.

Comparison of OMI NO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; observations and their seasonal and weekly cycles with ground-based measurements in Helsinki

Abstract. We present the comparison of satellite-based OMI (Ozone Monitoring Instrument) NO2 products with ground-based observations in Helsinki. OMI NO2 total columns, available from NASA's standard product (SP) and KNMI DOMINO product, are compared with the measurements performed by the Pandora spectrometer in Helsinki in 2012. The relative difference between Pandora no. 21 and OMI SP total columns is 4 and −6 % for clear-sky and all-sky conditions, respectively. DOMINO NO2 retrievals showed slightly lower total columns with median differences about −5 and −14 % for clear-sky and all-sky conditions, respectively. Large differences often correspond to cloudy fall–winter days with solar zenith angles above 65°. Nevertheless, the differences remain within the retrieval uncertainties. The average difference values are likely the result of different factors partly canceling each other: the overestimation of the stratospheric columns causes a positive bias partly compensated by the limited spatial representativeness of the relatively coarse OMI pixel for sharp NO2 gradients. The comparison between Pandora and the new version (V3) of OMI NO2 retrievals shows a larger negative difference (about −30 %) than the current version (V2.1) because the revised spectral fitting procedure reduces the overestimation of the stratospheric column. The weekly and seasonal cycles from OMI, Pandora and NO2 surface concentrations are also compared. Both satellite- and ground-based data show a similar weekly cycle, with lower NO2 levels during the weekend compared to the weekdays as a result of reduced emissions from traffic and industrial activities. The seasonal cycle also shows a similar behavior, even though the results are affected by the fact that most of the data are available during spring–summer because of cloud cover in other seasons. This is one of few works in which OMI NO2 retrievals are evaluated in a urban site at high latitudes (60° N). Despite the city of Helsinki having relatively small pollution sources, OMI retrievals have proved to be able to describe air quality features and variability similar to surface observations. This adds confidence in using satellite observations for air quality monitoring also at high latitudes.

Experimental investigation of precast concrete based dry mechanical column-column joints for precast concrete frames

Summary This paper proposed a precast concrete-based dry mechanical joint for fully-restrained moment connections which can be used to connect reinforced concrete precast columns. In the proposed connections, a pair of steel plates is provided and connected by high-strength bolts to transfer axial loads and moments. One plate is installed at the bottom of upper columns, and another one is placed on the top of lower columns. The stiffness of the column plates is determined to enable axial loads and the moment to be transferred at joints, providing a fully-restrained moment connection between columns. The structural behavior of the moment connections was evaluated through experimental and analytical investigations. Through extensive experimental investigations, columns jointed with plates capable of sufficient stiffness and strength demonstrated structural behavior similar to those of conventional columns. The plate deformations which fail to transfer the moment were not prevented with columns jointed by plates incapable of providing sufficient stiffness and strength. A good match in terms of the load–displacement relationship and plate deformation was also demonstrated between the finite element analysis based prediction and the test data for all specimens. The introduced connections will contribute to modular offsite construction for buildings and heavy industrial plants.

골조-전단벽 구조에서 수평강성의 향상을 위한 기둥과 전단벽 단면적의 배분

The research intended to search the optimal section area apportionment of columns and shear walls for improvement of lateral stiffness in frame-shear wall structure, using MIDAS-Gen. In this study, the main variables of analysis research were the section area ratios of column, the change of section area between the upper and lower columns and the change of thickness between the upper and lower shear walls. In order to find out the optimal section area apportionment of columns and shear walls for improvement of lateral stiffness in frame-shear wall structure, we examined the 30 stories reinforced concrete building. The results of this analysis study indicated that the section area ratios of column, the change of section area between the upper and lower columns, the change of thickness between the upper and lower shear walls had an impact upon the lateral stiffness in frame-shear wall structure. Moreover, it is showed that the research results can give help in obtaining the structural design data for finding out the optimal section area apportionment of columns and shear walls for improvement of lateral stiffness in frame-shear wall structure.

Retrieving Neptune’s aerosol properties from Keck OSIRIS observations. I. Dark regions

We present and analyze three-dimensional data cubes of Neptune from the OSIRIS integral-field spectrograph on the 10-m W.M. Keck II telescope, from 26 July 2009. These data have a spatial resolution of 0.035/pixel and spectral resolution of R ∼3800 in the H (1.47–1.80 µm) and K (1.97–2.38 µm) broad bands. We focus our analysis on regions of Neptune’s atmosphere that are near-infrared dark – that is, free of discrete bright cloud features. We use a forward model coupled to a Markov chain Monte Carlo algorithm to retrieve properties of Neptune’s aerosol structure and methane profile above ∼4 bar in these near-infrared dark regions.We construct a set of high signal-to-noise spectra spanning a range of viewing geometries to constrain the vertical structure of Neptune’s aerosols in a cloud-free latitude band from 2–12°N. We find that Neptune’s cloud opacity at these wavelengths is dominated by a compact, optically thick cloud layer with a base near 3 bar. Using the pyDISORT algorithm for the radiative transfer and assuming a Henyey-Greenstein phase function, we observe this cloud to be composed of low albedo (single scattering albedo =0.45−0.01+0.01), forward scattering (asymmetry parameter g=0.50−0.02+0.02) particles, with an assumed characteristic size of ∼1µm. Above this cloud, we require an aerosol layer of smaller (∼0.1µm) particles forming a vertically extended haze, which reaches from the upper troposphere (0.59−0.03+0.04 bar) into the stratosphere. The particles in this haze are brighter (single scattering albedo =0.91−0.05+0.06) and more isotropically scattering (asymmetry parameter g=0.24−0.03+0.02) than those in the deep cloud. When we extend our analysis to 18 cloud-free locations from 20°N to 87°S, we observe that the optical depth in aerosols above 0.5 bar decreases by a factor of 2–3 or more at mid- and high-southern latitudes relative to low latitudes.We also consider Neptune’s methane (CH4) profile, and find that our retrievals indicate a strong preference for a low methane relative humidity at pressures where methane is expected to condense. When we include in our fits a parameter for methane depletion below the CH4 condensation pressure, our preferred solution at most locations is for a methane relative humidity below 10% near the tropopause in addition to methane depletion down to 2.0–2.5 bar. We tentatively identify a trend of lower CH4 columns above 2.5 bar at mid- and high-southern latitudes over low latitudes, qualitatively consistent with what is found by Karkoschka and Tomasko (2011), and similar to, but weaker than, the trend observed for Uranus.