Are small communities at risk of population loss?

Small communities almost universally worry about out-migration and the negative effects of out-migration on community viability. Using Oregon community-level data and applying the threshold estimation method of Hansen (Econometrica 68(3):575–603, 2000), we are able to identify population thresholds that distinguish small communities from their larger counterparts based on significant structural differences in factors affecting net migration. Our results suggest that smaller communities are more at risk of population decline than larger ones. After controlling for spatial spillovers from neighboring communities, the average net migration rate is 3 % in the larger communities (roughly above 5,000 population), 2 % in the mid-sized communities (roughly between 1,250 and 5,000) and $-3$  % in the smallest communities (roughly less than 1,250). Other things equal, geographic isolation from large cities and low wage rates provide some protection from net out-migration for the smallest communities, but even for the smallest places, a larger population base lowers the risk of net out-migration.     

The mystery of the “spinning statue” at Manchester Museum

Abstract

This paper discusses the emergence, and impact, of public perceptions of Ancient Egypt and diverse ideas of “magic” at the Manchester Museum, following the huge response to the episode of the “spinning statuette.” In June 2013, a video of an Egyptian statuette spinning of its own accord in its case in the Egypt Gallery of the Manchester Museum went viral. During the media storm that followed the publication of the video, many hinted at a “magic event,” which could be related to popular perceptions of Ancient Egypt: ideas from movies and popular culture were widely used to explain and comment, often ironically, on the episode. At the same time, in the museum galleries people were jostling to see the statuette and questioning the museum staff. Therefore, this paper will observe how media and museum audiences have used the concept of “magic” in relation to the spinning statuette: what beliefs and attitudes towards “magic” emerge from these comments? Why was the museum criticized for suggesting a “magic” connection? And what have been the outcomes of the episode for the museum and for our understanding of public perceptions of Ancient Egypt?     

Behaviour of composite cellular steel — Concrete beams at elevated temperatures

The behaviour of composite cellular floor beams is becoming important as such members are increasingly used in multistorey buildings. In the event of fire, this issue becomes increasingly critical, particularly for exposed steelwork. In a fire situation, a composite beam has a much higher perimeter area exposed to fire in its lower web-flange section than in the upper web-flange section, and so the temperature distribution across a composite beam is usually non-uniform. The reduction in fire of the strength and stiffness of the material properties of the perforated steel beam, as well as differential thermal expansion, therefore becomes an important influence on the overall behaviour of the composite beam. The objective of this research is to enhance the level of understanding of the generic behaviour of composite cellular floor beams in fire conditions. In this paper, three-dimensional nonlinear finite element models of composite cellular floor beams have been developed, taking into consideration the influence of the changes in material properties with temperature. Experimental data from furnace tests on cellular composite floor beams obtained from previous research work has been used to validate the FE models. An analytical model based on existing design guides is also presented in this paper. It is concluded that finite element analysis results are in good agreement with the experimental data, and all the failure modes have been accurately predicted. The proposed simplified analytical methods show reasonable agreement with the test and FE results, and are always conservative.     

Behavior of steel fiber–reinforced high-strength concrete at medium strain rate

Impact compression experiments for the steel fiber–reinforced high-strength concrete (SFRHSC) at medium strain rate were conducted using the split Hopkinson press bar (SHPB) testing method. The volume fractions of steel fibers of SFRHSC were between 0 and 3%. The experimental results showed that, when the strain rate increased from threshold value to 90 s^-1, the maximum stress of SFRHSC increased about 30%, the elastic modulus of SFRHSC increased about 50%, and the increase in the peak strain of SFRHSC was 2-3 times of that in the matrix specimen. The strength and toughness of the matrix were improved remarkably because of the superposition effect of the aggregate high-strength matrix and steel fiber high-strength matrix. As a result, under impact loading, cracks developed in the SFRHSC specimen, but the overall shape of the specimen remained virtually unchanged. However, under similar impact loading, the matrix specimens were almost broken into small pieces.     

Selectivity of new inorganic ion–exchangers based on oxides of titanum and manganese at sorpion of lithium from aqueous media

We have obtained new composite materials of TiO₂–MnO₂ saturated with lithium ions and treated at 500 and 600°C. Using methods of low-temperature adsorption of nitrogen, infrared and X-ray spectroscopy their structural properties were investigated. It has been shown that given ion–exchangers display substantial selectivity at sorption of lithium ions with respect to other cations.     

Review of Urban Planning of Beijing(1949 – 1960): A Masterpiece of Planning History Study of Beijing at the Early Stage of the People's Republic of China

<正>Urban Planning of Beijing(1949 – 1960)Author: Li Hao Year: 2022Publisher: China Architecture & Building Press ISBN: 9787112281725(447 pages, in Chinese)The 1950s is an important period in terms of the urban planning history study of China. It is not only the initial and foundation stage of China’s modern urban planning, with profound influence on contemporary urban planning,     

Field performance evaluation of a newly developed PM₂.₅ sampler at IIT Kanpur

In order to meet the challenges of growing air pollution for a developing nation and to measure the ambient fine particles (PM_2.5, particles having aerodynamic diameter less than 2.5 μm) on routine basis an air sampler was designed, developed and evaluated in the field. The impactor removes particles greater than 2.5 μm from the air stream via impacting them onto a vacuum grease substrate and finer particles get eventually collected on a backup filter. Various impactor nozzles with conical geometry were designed based on the published theoretical design equations. A detail parametric investigation was carried out which resulted in the optimum impactor nozzle design. For this exercise, a novel dry aerosol generator was employed in addition to the well known time-of-flight instrument, APS (Aerodynamic Particle Sizer, Model 3021, TSI Inc.). The average particle losses for the impactor nozzle as well as the sampler body were below 10% and the overall pressure drop (including a backup 47 mm filter) through the PM_2.5 sampler was only 2 in. of H₂O. This developed PM_2.5 sampler operates at a flow rate of 15 LPM. Field performance of this sampler was evaluated through co-located sampling with a high volume PM_2.5 reference sampler (HVS, GEM-BLI Model 2360, Tisch Environment Instrument) within the IIT Kanpur campus. The sampling period was 10 h long and it was carried out on six different days. The entire sets of filters were analyzed gravimetrically followed by their chemical analysis for elemental and anionic analyses. The particle mass, elemental, and anionic concentrations obtained with this newly developed PM_2.5 sampler as well as those from the reference HVS sampler showed moderate to good correlation.     

New landscapes of conflict: land-use competition at the urban–rural fringe

Land-use conflict research generally focuses on conflicts where pre-existing opponents respond to the introduction of a new unwanted land-use. We select a 2008 land-use conflict to explore an understudied scenario: urban–rural fringe (URF) expansion can introduce new opposing stakeholders into areas with pre-existing unwanted land-uses. We use spatial analysis methods to measure the rate and direction of URF expansion in relation to a vacated cement facility that had been approved for revitalisation in 2008, motivating a land-use conflict between competing stakeholders. Findings indicate that the cement facility and surrounding land-uses had been continuously used for similar noxious activities since 1964, but URF expansion changed the area’s surrounding landscape from rural-majority to urban-majority prior to the 2008 land-use conflict. The association between URF expansion and space-related drivers of land-use conflict is a necessary consideration when studying increasingly urbanised landscapes.     

Human Factors in the Analysis of the ＂Tram-Car Drivers＂ at Intersections

The modem tramway has resurfaced as the cure to today＇s urban transport problems such as pollution, road congestion and uneven access to transit. However, trams at intersections often experience frequent and extended delays due to vehicles crossing the tram tracks. There is an increased potential for conflict between trams and vehicles at these locations and crashes are common. The question of the effects of human factors on trams crossroads safety has been little dealt with in literature. The general aim of this article is to further knowledge about the influence of tramway and surrounding environment on car＇s driver behavior at intersections. Understanding these influences, involve conducting a systematic review of the cognitive tasks related to driving and identifying the hazards that can arise at each task, and what factors can make these more or less likely to arise, considering the environmental design at intersections and behavioral factors. To achieve that, the HAZOP （Hazard and Operability Study） approach is conducted for this study. Concerning data collection, the methodology includes site visits to record user behavior and questionnaires to determine the opinion, concerns and knowledge of car drivers in interaction with the tram environment.     

Analyses of the grouting results for a section of the APSE tunnel at Äspö Hard Rock Laboratory

The grouting results for a tunnel at a depth of 450 m in crystalline rock at Äspö HRL were studied. The aims were to investigate whether the methodology used resulted in a successful grouting design and producing a sufficiently dry tunnel, and whether grout penetration and inflow into the finished tunnel corresponded to the predictions. An analysis was made of data from an original cored borehole, drilled before the tunnel was constructed and mapped thoroughly with regard to fractures and transmissivities. The predicted inflow into the tunnel was calculated and found to be four times higher than the measured inflow. The latter was 5 l/min along the 70 m tunnel, considered to be a good result at the current depth. New cored control boreholes were drilled along a section of the tunnel. The inflow positions and quantities in these holes, and the positions of grout found in the corresponding cores, were compared with the data from the original borehole. It was found that at the predicted positions of larger fractures, grout was observed and there was no inflow, showing that these had been successfully sealed. At the predicted positions of small fractures, no grout was visible in the cores, and small inflows showed that the grout had not sealed these fractures. The results indicated that cement-based grout successfully sealed fractures down to a hydraulic aperture of about 50 μm but not below 30 μm. This concurs with the initial design aimed at sealing fractures larger than 50 μm.     

Acoustic emission monitoring of rockbursts during TBM-excavated headrace tunneling at Jinping Ⅱ hydropower station

To better understand the mechanical properties of marble at Jinping II hydropower station, this paper examines the changes of brittle rocks in excavation damaged zones(EDZs) before and after excavation of tunnel with the tunnel boring machine(TBM). The paper attempts to employ the acoustic emission(AE) to study the AE characteristics and distribution of rockburst before and after TBM-excavated tunnel. It is known that the headrace tunnel #2, excavated by the drill-and-blast(D&B) method, is ahead of the headrace tunnel #3 that is excavated by TBM method. The experimental sub-tunnel #2–1, about 2000 m in depth and 13 m in diameter, between the two tunnels is scheduled. In the experimental sub-tunnel #2–1, a large number of experimental boreholes are arranged, and AE sensors are installed within 10 m apart from the wall of the headrace tunnel #3. By tracking the microseismic signals in rocks, the location, frequency, quantity, scope and intensity of the microseismic signals are basically identifed. It is observed that the AE signals mainly occur within 5 m around the rock wall, basically lasting for one day before tunnel excavation and a week after excavation. Monitoring results indicate that the rockburst signals are closely related to rock stress adjustment. The rock structure has a rapid self-adjustment capacity before and after a certain period of time during tunneling. The variations of rock stresses would last for a long time before reaching a fnal steady state. Based on this, the site-specifc support parameters for the deep tunnels can be accordingly optimized.     

Key technologies and risk management of deep tunnel construction at Jinping Ⅱ hydropower station

The four diversion tunnels at Jinping Ⅱ hydropower station represent the deepest underground project yet conducted in China, with an overburden depth of 1500-2000 m and a maximum depth of 2525 m.The tunnel structure was subjected to a maximum external water pressure of 10.22 MPa and the maximum single-point groundwater inflow of 7.3 m~3/s. The success of the project construction was related to numerous challenging issues such as the stability of the rock mass surrounding the deep tunnels, strong rockburst prevention and control, and the treatment of high-pressure, large-volume groundwater infiltration. During the construction period, a series of new technologies was developed for the purpose of risk control in the deep tunnel project. Nondestructive sampling and in-situ measurement technologies were employed to fully characterize the formation and development of excavation damaged zones(EDZs), and to evaluate the mechanical behaviors of deep rocks. The time effect of marble fracture propagation, the brittleeductileeplastic transition of marble, and the temporal development of rock mass fracture and damage induced by high geostress were characterized. The safe construction of deep tunnels was achieved under a high risk of strong rockburst using active measures, a support system comprised of lining, grouting, and external water pressure reduction techniques that addressed the coupled effect of high geostress, high external water pressure, and a comprehensive early-warning system. A complete set of technologies for the treatment of high-pressure and large-volume groundwater infiltration was developed. Monitoring results indicated that the Jinping II hydropower station has been generally stable since it was put into operation in 2014.     

Scavenging of gaseous mercury by acidic snow at Kuujjuarapik, Northern Québec

One fate of gaseous elemental mercury (GEM) in the Arctic has been identified as gas phase oxidation by halogen-containing radicals, leading to abrupt atmospheric mercury depletion concurrent with ozone depletion. Rapid deposition of oxidized mercury leads to snow enrichment in mercury. In this report, we describe experiments that demonstrate the ability of snow to directly scavenge atmospheric mercury. The study was conducted at Kuujjuarapik, Québec, Canada (latitude 55 degrees 17'N). A mercury depletion event (MDE) caused the mercury concentration in the surface snow of the coastal snowpack to double, from (9.4+/-2.0) to (19.2+/-1.7) ng/L. Independent of the MDE, mercury concentrations increased five-fold, from (10.0+/-0.1) to (51.4+/-6.0) ng/L, upon spiking the snow with 500 microM hydrogen peroxide under solar irradiation. Total organic carbon in the spiked irradiated snow samples also decreased, consistent with the formation of strongly oxidizing species. The role of the snowpack in releasing GEM to the atmosphere has been reported; these findings suggest that snow may also play a role in enhancing deposition of mercury.     

Long-term simulation of the activated sludge process at the Hanover-Gümmerwald pilot WWTP

The aim of this study was to obtain a validated model, consisting of the Activated Sludge Model No. 3 (ASM3) and the EAWAG bio-P module, which could be used as a decision tool for estimating the maximum allowable peak flow to wastewater treatment plants during stormwater conditions. The databases used for simulations originated from the Hanover-Gummerwald pilot plant subjected to a series of controlled, short-term hydraulic shock loading experiments. The continuous influent wastewater composition was generated using on-line measurements of only three parameters (COD, N-NH4+, P-PO4 3-). Model predictions were compared with on-line data from different locations in the activated sludge system including the aerobic zone (concentrations of N-NH4+, N-NO3-) and secondary effluent (concentrations of P-PO4 3-). The simulations confirmed experimental results concerning the capabilities of the system for handling increased flows during stormwater events. No (or minor) peaks of N-NH4+ were predicted for the line with the double dry weather flowrate, whereas peaks of N-NH4+ at the line with the quadruple dry weather flowrate were normally exceeding 8 g Nm(-3) (similar to the observations).     

Guillaume at Bennelong 餐厅

重建前悉尼歌剧院"Guillaume at Bennelong"餐厅的创意可分为三个部分.首先,设计师运用采光技术加强了覆盖餐厅的歌剧院拱顶壳面结构造型与规模的视觉效果.除了加强建筑总体造型给人的震撼性外,设计师还必须为餐厅营造出一个亲切的用餐环境.凭着独特的照明与采光设计,设计师将一系列或大或小的创意灯饰,巧妙地安置在餐厅的各个部分,为餐厅增添了许多亲密的感官享受氛围.     

Chemical composition of rainwater at a coastal town on the southwest of Europe: what changes in 20 years?

Rainwater was collected at the Portuguese west coast between September 2008 and September 2009, and analysed for pH, conductivity, and Cl⁻, NO₃⁻, SO₄²⁻, and NH₄⁺ concentrations. Results of rainwater chemical composition were compared with those obtained at the same site between 1986 and 1989. In both collection periods rainwater was predominantly (≈ 80%) associated to oceanic air masses. The rainwater concentration of H⁺ was in the same range as twenty years ago. A clear decrease of non sea salt sulphate (NSS-SO₄²⁻) was observed in 2008-2009 relatively to 1986-1989, not only in samples with origin in central and northern Europe, but also in samples from Atlantic Ocean and Mediterranean. This decrease indicates that SO₂ emissions were reduced, which may be due to a lower content of sulphur in oil by-products. A decrease was also observed in NH₄⁺ concentration in 2008-2009. On the contrary an increase of NO₃⁻ concentration was observed for samples of all origins in 2008-2009 relatively to 1986-1989, which was particularly high (more than 3 fold) for samples with origin in Atlantic Ocean, suggesting the incorporation of this ion by rainout at the sampling site. The contribution of local sources is indeed suggested by the moderate negative correlation of NH₄⁺, NO₃⁻ and NSS-SO₄²⁻ with rainwater volume. The high increase of NO₃⁻ concentration can be attributed to the increase of local vehicular and industrial emissions in the sampling area.     

Plus,plus ça change at the museum of modern art in New York

The selection of Yoshio Taniguchi, in 1997, to design the Museum of Modern Art's enormous expansion was generally considered conservative, if not outright old-fashioned. When the museum reopened in November 2004, most critics described the new scheme as ‘contextual’ or ‘subtle’, and noted that the architect had said he had tried ‘to make the architecture go away’. Now that enough time has passed to blur expectations, Jayne Merkel looks at MoMA as it is today. She contends that the choice was progressive in exactly the way the museum has been all along, and that the architecture is very much there. Copyright © 2006 John Wiley & Sons, Ltd.     

Examining Open Data at the Urban Level: An Exploration of “Wellbeing Toronto”

This paper examines how Wellbeing Toronto (WT)—a free, open data, GIS tool that allows users to map information—has evolved into an extensive data repository with robust data analysis capabilities. Explored is the progress of open data scholarship in relation to municipal government and civic participation. Based on this, the authors note the following: (1) as open data becomes increasingly prevalent, a more varied understanding of the organization and structure of municipal government may emerge. (2) There is a need for measures of civic engagement to move beyond data co-production towards an organization-based interactive approach.     

Flexural retrofitting of RC beams using external bars at soffit level – An experimental study

Throughout the globe, huge stock of buildings become vulnerable to damage due to aging, rebar corrosion, and natural hazards, particularly earthquake. Section enlargement, bonded steel plating, external post-tensioning and FRP composites wrapping are some of the techniques being widely followed to retrofit various structural elements. Each technique has at least one or more number of limitations. High cost, difficulty in execution, reduction in headroom, loss of aesthetic value, increase in self-weight, careful surface preparation, de-bonding failure are some of the innate limitations of these techniques. A maiden attempt has been made by the authors to devise a new technique to retrofit RC beams with external reinforcement. The proposed method overcomes most of the drawbacks of the above said existing methods. Some work has already been reported on external reinforcement by keeping the reinforcement at the sides of the beam using deflectors, mechanical anchoring devices and strengthening end anchorage zones. The reported technique in the present work overcomes all the drawbacks of the above method. The authors propose the external bars to be kept at the soffit level of the beam section, thus eliminating the use of deflectors, mechanical anchoring devices and making it amenable, simple and effective. Additional advantages of the present technique are the enhanced moment carrying capacity, reduced deflection and crack width and improved ductility.