[en] Zernike phase contrast is a useful technique for nanoscale X-ray computed tomography (CT) imaging of materials with a low X-ray absorption coefficient. It enhances the image contrast by phase shifting X-ray waves to create changes in amplitude. However, it creates artifacts that hinder the use of traditional image segmentation techniques. We propose an image restoration method that models the X-ray phase contrast optics and the three-dimensional image reconstruction method. We generate artifact-free images through an optimization problem that inverts this model. Though similar approaches have been used for Zernike phase contrast in visible light microscopy, this optimization employs an effective edge detection method tailored to handle Zernike phase contrast artifacts. We characterize this optics-based restoration method by removing the artifacts in and thresholding multiple Zernike phase contrast X-ray CT images to produce segmented results that are consistent with the physical specimens. We quantitatively evaluate and compare our method to other segmentation techniques to demonstrate its high accuracy

[en] We report on the MR imaging of an anomalous medial meniscus with a tear in a 41-year-old man. Anomaly of the medial meniscus is rare and difficult to diagnose clinically. The MR images contributed to the pre-arthroscopic diagnosis and arthroscopy confirmed the lesion. The anomalous meniscus was not related to the symptoms. (orig.)

[en] These velocity map imaging experiments characterize the photolytic generation of one of the two radical intermediates formed when OH reacts via an addition mechanism with allene. The CH₂CCH₂OH radical intermediate is generated photolytically from the photodissociation of 2-chloro-2-propen-1-ol at 193 nm. Detecting the Cl atoms using [2+1] resonance-enhanced multiphoton ionization evidences an isotropic angular distribution for the Cl+CH₂CCH₂OH photofragments, a spin-orbit branching ratio for Cl(²P_1/2):Cl(²P_3/2) of 0.28, and a bimodal recoil kinetic energy distribution. Conservation of momentum and energy allows us to determine from this data the internal energy distribution of the nascent CH₂CCH₂OH radical cofragment. To assess the possible subsequent decomposition pathways of this highly vibrationally excited radical intermediate, we include electronic structure calculations at the G3//B3LYP level of theory. They predict the isomerization and dissociation transition states en route from the initial CH₂CCH₂OH radical intermediate to the three most important product channels for the OH+allene reaction expected from this radical intermediate: formaldehyde+C₂H₃, H+acrolein, and ethene+CHO. We also calculate the intermediates and transition states en route from the other radical adduct, formed by addition of the OH to the center carbon of allene, to the ketene+CH₃ product channel. We compare our results to a previous theoretical study of the O+allyl reaction conducted at the CBS-QB3 level of theory, as the two reactions include several common intermediates

[en] In this paper, an attempt has been made to enhance the fracture toughness (Kc) of boride layer using multi-component (Ni, Cr and B) laser bonding. The fracture toughness of continuously pack borided, interrupted pack borided and multi-component (Ni, Cr and B) laser borided steel specimens was measured using Vickers microindentation fracture toughness test as per ASTM E384 standard. The fracture toughness of continuously pack borided layer was - 3.3 MPa.m"1"/"2. The fracture toughness of interrupted boride layer was in the range of - 4.9 MPa.m"1"/"2. The fracture toughness of multi-component (Ni, Cr and B) laser borided layer was in the range of 13.8 - 18.3 MPa.m"1"/"2. A significant improvement in fracture toughness of laser treated specimens was observed from the experimental results. This may be due to better distribution of boron, nickel, chromium and other alloying elements due to laser treatment and relatively more uniform boride layer as compared with continuously pack borided layer and interrupted pack borided layer. (paper)

[en] Following spinal instrumentation and fusion, differentiating between successful arthrodesis and pseudoarthrosis on imaging can be challenging. Interpretation of such examinations requires understanding both the expected evolution of postoperative findings and the subtle indicators of pseudoarthrosis across multiple imaging modalities. Due to this level of intricacy, many clinicians lack familiarity with the subject beyond the more rudimentary concepts. This review provides an in-depth overview of the imaging of the post-operative spine, with particular emphasis on differentiating between pseudoarthrosis and arthrodesis. A comprehensive overview of imaging of the post-operative spine is given, including the most common imaging modalities utilized, the expected post-operative findings, imaging findings in pseudoarthrosis, and imaging definitions of fusion. Differentiating between pseudoarthrosis and arthrodesis in the postoperative spine is complex, and requires a robust understanding of various findings across many different modalities.

[en] The work carried out deals with effect of variation in compression ratio (VCR) on engine performance and emission by applying thermal barrier coating on to engine parts for improving engine performance when biodiesel (mixed milk scum and safflower) is used as alternative fuel and the layer of thermal coating was made of Alumina-Titanium oxide (Al₂O₃/TiO₂) plasma coated on to the base of NiCrAl. The work also deal with experimental analysis of performance and exhaust emission characteristics of diesel-biodiesel blends use in single cylinder 4-stroke with varying compression ratio (VCR) i.e. 14:1, 16:1- 18:1 using biodiesel blends i.e. B20, B40,B60,B80 and B100 with load variation from a load to full load and compare with base. The result showed a reduction in specific fuel consumption.CO and HC emissions are slightly more than the conventional coated diesel engine at low and medium loads but lesser at higher load where NO_x is reduced. (paper)

[en] Highlights: • We find a 45% reduction in household expenditure on energy. • Consumption of liquefied petroleum gas declines by 6 to 7 kg per month. • Time spent foraging for firewood declines by 85%. • Without subsidies, the estimated payback period for a digester is 11 to 14 years. • Sustaining digester uptake requires generation of additional financial benefits. - Abstract: Biogas has been promoted as a renewable, cleaner and cheaper energy source. While there are several initiatives promoting the use of biogas, credible analyses of its effects on the use of alternative energy sources and energy related expenditure are limited. This study uses panel data from households engaged in dairy farming in rural East Java to assess the impact of a household level programme, which promotes the construction of digesters that produce biogas, on energy use and expenditures. Both a difference-in-difference analysis and a pipeline comparison show that the use of digesters leads to a sharp reduction in energy related expenditures and a reduction in the use of firewood and liquefied petroleum gas. However, without subsidies, the payback period of between 11 and 14 years, albeit based only on reductions in energy costs accruing from investing in a digester, is perhaps too long to justify the investment.

[en] The role of gluons in the structure of the nucleon and light nuclei is investigated using lattice quantum chromodynamics (QCD) calculations. The first moment of the unpolarised gluon distribution is studied in nuclei up to atomic number A=3 at quark masses corresponding to pion masses of m_π∼450 and 806 MeV. Nuclear modification of this quantity defines a gluonic analogue of the EMC effect and is constrained to be less than ∼10% in these nuclei. This is consistent with expectations from phenomenological quark distributions and the momentum sum rule. In the deuteron, the combination of gluon distributions corresponding to the b₁ structure function is found to have a small first moment compared with the corresponding momentum fraction. The first moment of the gluon transversity structure function is also investigated in the spin-1 deuteron, where a non-zero signal is observed at m_π∼806 MeV. In conclusion, this is the first indication of gluon contributions to nuclear structure that can not be associated with an individual nucleon.

[en] The Fourier transform infrared (FT-IR) spectral data of two nerve agent simulants, diisopropyl methyl phosphonate (DIMP) and dimethyl methyl phosphonate (DMMP), are used as test cases to determine the spectral resolution that gives optimal pattern recognition performance. DIMP is used as the target analyte for detection, while DMMP is used to test the ability of the automated pattern recognition methodology to detect the analyte selectively. Interferogram data are collected by using a Midac passive FT-IR instrument. The methodology is based on the application of pattern recognition techniques to short segments of single-beam spectra obtained by Fourier processing the collected interferogram data. The work described in this article evaluates the effect of varying spectral resolution on the pattern recognition results. The objective is to determine the optimal spectral resolution to be used for data collection. The results of this study indicate that the data with a nominal spectral resolution of 16 cm^-1 provide sufficient selectivity to give pattern recognition results comparable to that obtained by using higher resolution data. We found that, while higher resolution does not increase selectivity sufficiently to provide better pattern recognition results, lower resolution decreases selectivity and degrades the pattern recognition results. These results can be used as guidelines to maximize detection sensitivity, to minimize the time needed for data collection, and to reduce data storage requirements. (c) 2000 Society for Applied Spectroscopy

[en] Highlights: • Pipeline comparison analysis of solar home systems on energy consumption in Kenya. • Results show an increased use of LED lamps, reduction in dirty lamps and kerosene. • Increased satisfaction results from better lighting and more time for TV watching. • Changes in energy use and phone charging lead to monthly savings of EUR 1.60. • Setting the costs against the combined benefits of SHS suggests a positive payoff. This paper assesses the impact of solar home systems (SHS) on energy consumption and energy-related expenditures among Kenyan households. Based on a pipeline comparison approach of more than a thousand households, we find that access to a SHS leads to a net increase of 24 to 36 min in daily lighting use due to a 3 h increase in the use of LED lamps, accompanied by a reduction in the use of “dirty” lamps. We also find a one litre reduction in the monthly use of kerosene for lighting. These changes in energy use along with a decline in the cost of charging mobile phones leads to a reduction in overall monthly expenditure of KSh 193 (about EUR 1.60). For the most popular SHS, these economic effects translate into a payback period of about six years. In addition to the economic benefits, we find small positive environmental effects, increased satisfaction from better quality lighting and an increase in time spent watching TV. Setting the costs against the combined benefits of SHS suggests a positive payoff for this particular off-grid electricity option and a viable way forward in providing off-grid energy solutions with a wide range of functionalities in developing countries.