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Soil Rllage and compacRon influence soil properRes and processes like porosity, bulk density, water content, drainage, and infiltraRon which ulRmately affects soil quality and health. Nearsurface geophysical techniques such as Ground-PenetraRng Radar (GPR) and ElectromagneRc InducRon (EMI) are being increasingly uRlized to esRmate soil water content. However, there is a lack of studies examining the role of soil Rllage and compacRon on soil properRes and processes using geophysical proxies. Accordingly, the objecRve of this study was to elucidate the influence of soil compacRon on responses of GPR direct ground wave velocity (VDGW), amplitude (ADGW), and apparent electrical conducRvity (ECa) measured using EMI in a boreal podzolic soil. Proxy data: VDGW, ADGW and ECa, were collected using an EMI sensor and a 500 MHz center frequency GPR system under three stages, i.e., afer Rllage, afer 4- and 10-Rmes roller passes. Undisturbed soil samples were collected to measure bulk density as the soil compacRon index and correlaRons were assessed between proxies and soil bulk density. Moderate posiRve correlaRons were found between average bulk density (0-30 cm depth) and ADGW (r=0.548, p=0.001), and ECa (r=0.633, p=0.001), while a moderate negaRve correlaRon was found between bulk density and VDGW (r= -0.464, p=0.030). Preliminary results reveal that mapping soil bulk density at the field-scale using GPR and EMI can potenRally capture the effects of Rllage or compacRon on the variability of soil bulk density and related properRes or processes. Therefore, the effect of agricultural pracRces on soil properRes can be esRmated non-destrucRvely with proxies of GPR or EMI to advance precision agriculture.

Reliability and cost-effectiveness are very important factors in welding processes used in a wide range of manufacturing industries. Selection of welding processes varies widely from application to application and from industry to industry. Generally, it is difficult to obtain quality weldments with desired mechanical properties economically while maintaining high reliability. Furthermore, it is desirable to perform welding operations that can satisfy individual applications and requirements specifically, and produce tailor-made weldments to suit specific requirements. This paper presents the ability of process optimization in customizing required quality weldments with respect to desired mechanical properties. Gas Metal Arc Welding (GMAW) for samples of mild steel was performed in optimizing input weld-parameters. Welded samples, produced with different combinations of welding parameters, were investigated for their mechanical properties and metallographically characterized to explain the observed property variation. In addition to finding optimum parameters for a quality weld, a critical welding current (CWC) at which a brittle weldment is formed could also be discovered during this work. It is expected that process optimization for the customization precisely conceivable for tailor-made applications through modeling and simulation with software developed based on further research to improve welding quality in the global manufacturing industry.

Background and Aim There is increasing prevalence of inflammatory bowel disease (IBD) in Asia, but Sri Lankan data on the state of epidemiology and clinical course of IBD are scarce. Methods A hospital‐based study was done by recruiting IBD patients who permanently reside in the Central Province (population 2.57 million, 12.6% of Sri Lankan population) of Sri Lanka. Cases were confirmed by standard criteria and data were collected from health records and patient interviews at clinic visits and hospital admissions. Results There were 200 cases of IBD; (ulcerative colitis [UC]—140, Crohn's disease [CD]—60, microscopic colitis—7). The crude prevalence rate of UC was 5.44/100 000 (95% CI 5.41–5.47/100 000) and CD was 2.33/100 000 (95% CI 2.31–2.35/100 000). Female to male ratios were 1:0.8 for UC but 1:1.5 for CD. Mean age at diagnosis was 42.0 and 31.9 years for UC and CD, respectively. One UC and one CD patient had positive family history of IBD. Among the UC patients, 60.7%, 24.3%, and 15% had proctitis, left sided, and extensive disease, respectively. At presentation, 62.1% of the UC patients have had moderately severe disease. 60% of the CD patients had only large bowel involvement and 80% had nonstricturing and nonpenetrating disease. Extra intestinal manifestations were present in 45.7% and 60.0% of UC and CD patients, respectively, in which peripheral arthralgia and arthritis being the commonest. 6.4% of UC and 23.3% of the CD patients (total of 23) required infliximab for induction of remission. Conclusion The prevalence of IBD in the Central Province of Sri Lanka is lower than other Asian and Western populations. There is a predominance of male gender and isolated colonic disease in CD patients. UC patients have an equal gender distribution and a higher proportion of proctitis. CD needed induction with infliximab than UC.

This paper investigates the feasibility of utilising blind bolts as shear connectors to develop demountable steel-concrete beams. The flexural behaviour of composite beams with two blind bolt types and welded stud connectors were experimentally investigated using full-scale beam specimens. A set of push-test specimens was tested based on the Eurocode 4 to compare the slip response of these connectors. The ultimate design loads of the test beams were calculated based on rigid plastic analysis (RPA) using the actual material properties. The beam experiments were simulated by using three-dimensional non-linear finite element models (FEMs). The material behaviour for concrete and steel in FEMs was described using concrete damage plasticity and steel plasticity models respectively. The FEMs were validated by comparing the load-midspan deflection curves of the beam specimens obtained from the experiments and modelling. The effects of the concrete compressive strength, steel yield strength and the shear connection ratio on the flexural behaviour of the composite beams were studied by utilising the validated FEMs. The experimental and numerical results suggest that the ability of the blind bolts to achieve and maintain composite action in steel-concrete beams under flexural loading is comparable to that of the welded stud connectors.

A fully automated system for the determination of δ13C and δ18O in atmospheric CO has been developed. CO is extracted from an air sample and converted into carbon dioxide (CO2) using the Schütze reagent. The isotopic composition is determined with an isotope-ratio mass spectrometer (IRMS) technique. The entire system is continuously flushed with high-purity helium (He), the carrier gas. The blank signal of the Schütze reagent is ~ 4 nmol mol−1, or 1–3 % of the typical sample size. The repeatability is 0.1 ‰ for δ13C and 0.2 ‰ for δ18O. The peak area allows for simultaneous determination of the mole fraction with an analytical repeatability of ~ 0.7 nmol mol−1 for 100 mL of ambient air (185.4 nmol mol−1 of CO). An automated single measurement is performed in only 18 min, and the achieved time efficiency (and small volume of sample air) allows for repetitive measurements practically.

Measurements of CO2, CO, N2O and CH4 mole fractions, O2/N2 ratios and the stable isotopes 13C and 18O in CO2 and CO have been performed in air samples from the highway tunnel Islisberg (Switzerland). The CO:CO2 ratios, with an average of (4.15±0.34) 5 ppb : ppm, are lower than reported by previous studies, pointing to a reduction in CO emissions from traffic. The 13C in CO2 reflects the isotopic composition of the fuel. 18O in CO2 is slightly depleted compared to the 18O in atmospheric O2, and shows significant variability. In contrast, the 13C values of CO show that significant fractionation takes place during CO destruction in the catalytic converter. 13C in CO is 10 enriched by 3% compared to the 13C in the fuel burnt, while the 18O content is similar to that of atmospheric O2. We compute a fractionation constant of (−2.7±0.7)% for 13C during CO destruction. The N2O:CO2 average ratio (1.8±0.2)×10−2 ppb : ppm is significantly lower than in past studies, showing a reduction in N2O emissions likely related to improvements in the catalytic technology. We also observed small CH4 emissions, with an average CH4 :CO2 ratio of (4.6±0.2)×10−2 ppb : ppm. The O2 :CO2 ratios of (−1.47±0.01) ppm : ppm are very close to the expected, theoretically calculated values.

Measurements of CO2, CO, N2O and CH4 mole fractions, O2/N2 ratios and the stable isotopes 13C and 18O in CO2 and CO have been performed in air samples from the Islisberg highway tunnel (Switzerland). The molar CO : CO2 ratios, with an average of (4.15 ± 0.34) ppb:ppm, are lower than reported in previous studies, pointing to a reduction in CO emissions from traffic. The 13C in CO2 reflects the isotopic composition of the fuel. 18O in CO 2 is slightly depleted compared to the 18O in atmospheric O2, and shows significant variability. In contrast, the δ13C values of CO show that significant fractionation takes place during CO destruction in the catalytic converter. 13C in CO is enriched by 3‰ compared to the 13C in the fuel burnt, while the 18O content is similar to that of atmospheric O2. We compute a fractionation constant of (-2.7 ± 0.7)‰ for 13C during CO destruction. The N2O : CO2 average ratio of (1.8 ± 0.2) × 10-2 ppb:ppm is significantly lower than in past studies, showing a reduction in N2O emissions likely related to improvements in the catalytic converter technology. We also observed small CH4 emissions, with an average CH4 : CO2 ratio of (4.6 ± 0.2) × 10−2 ppb:ppm. The O2 : CO2 ratios of (-1.47 ± 0.01) ppm:ppm are very close to the expected, theoretically calculated values of O2 depletion per CO2 enhancement.