Shell Lines Research Articles

Nasal obstruction in a 14 year old girl caused by a huge middle turbinate mucocele appearing radiologically as an inverted papilloma

Introduction: We present a case of a fourteen year old girl who presented with a large intra-nasal mass to the ENT team at a district general hospital in the UK. Presentation of case: The girl presented predominantly with nasal obstruction and some symptoms of allergic rhinitis. Imaging revealed a large lesion abutting the skull base and causing bony remodelling with marked septal deviation. Based both on CT and MRI imaging, the reporting (non-head and neck) radiologist suggested inverted papilloma as a differential diagnosis. Intra-operative exploration in fact revealed a very large left middle turbinate mucocele extending to the left frontal sinus. The mass was excised endoscopically without complications. Discussion: Although concha bullosa of the middle turbinate of the nose are common, development of a mucocele within them is far less common and for such a mucocele to develop to this size in a child is extremely rare. The egg shell lining of the lesion can be a tell-tale sign of their aetiology when taken alongside other radiological factors. This case highlights challenges in radiological diagnosis of intra-nasal masses in children, which can lead to delays and increased anxiety. Conclusion: When assessing nasal masses in children it is important to keep a wide differential due to the challenges of diagnosis. A close conversation should be had with local head and neck radiologists and, of course, where there is a unilateral nasal mass tissue sampling is essential and may be taken as part of a full excision where clinically indicated.

Fatigue life prediction and fracture mechanism of styrene-butadiene-styrene thermoplastic elastomer under uniaxial tension

The fatigue life and prediction of styrene-butadiene-styrene thermoplastic elastomer (SBS) under the action of uniaxial tension was investigated, and the fatigue fracture mechanism was analyzed. With the increases of amplitude and frequency, the fatigue life of SBS decreases. The fatigue life of SBS under the amplitude and frequency was predicted, and the shift factor was applied to predict the fatigue life of SBS at the other frequency and amplitude. With the increase of temperature, the fatigue life decreases first and then increases. The fatigue fracture surface presents crack source region, crack propagation region, and instantaneous fracture region. At – 40°C, the crack source region is rough, and the crack propagation region and instantaneous fracture region are rough with the rib morphology. With the increase of temperature at 23°C, the crack source region is relatively flat, and the crack propagation region presents the undulant surface. With the temperature further increased up to 50°C, the fracture surface is very flat, and the shell lines could be clearly seen. The crack growth rate of SBS increases with the increase of temperature. The gel structure of SBS is formed at high temperature through the chemical crosslinking.

Influence of novel polymer waterproofing membrane on mechanical properties of tunnel lining structure

The composite shell lining of tunnels uses an adhesive waterproofing membrane to replace the traditional sheet waterproofing membrane, which can improve the waterproofing performance of the tunnel and provide excellent mechanical characteristics. To calculate and design the lining structure, it is necessary to evaluate the influence of the existence of the bond interface on the mechanical behaviour of the lining structures. In this study, a four-point bending test was performed on a reinforced concrete beam with a novel polymer waterproofing membrane and the degree of composite action was quantitatively calculated. Under the bonding effect of the waterproofing membrane, the beam with the waterproofing membrane had a certain degree of composite action, and its strength and stiffness were also significantly improved compared with the beam with a sheet waterproofing membrane. ABAQUS software was used to establish the numerical calculation model of the beam with a spray-applied waterproofing membrane verified by testing, and the influence of the interface on its mechanical behaviour was analysed. The degree of composite action also increases with an increase in the waterproofing membrane thickness and interface stiffness.

Coaxing the Eclipsing Binary V367 Cygni out of Its Shell

Spectra that cover 0.63–0.69 μm with a spectral resolution ∼17,000 are presented of the W Serpentis system V367 Cygni. Absorption lines of Fe ii and Si ii that form in a circumsystem shell are prominent features, and the depths of these are stable with time, suggesting that the shell is smoothly distributed and well mixed. Further evidence of uniformity comes from modest radial velocity variations measured in the deepest parts of the shell lines. It is suggested that motions previously attributed to rotation of the shell are instead artifacts of contamination from the donor star spectrum. A donor star spectrum is extracted that is consistent with that of an early to mid-A giant. The depths of metallic lines in the donor spectrum vary with orbital phase, suggesting that spot activity covers a large fraction of the surface of that star. A spectrum of the accretion disk that surrounds the second star is also extracted, and similarities are noted with the emission spectra of Herbig Ae/Be stars. In addition to variations with orbital phase, Hα changes with time over timescales of no more than two orbits. A tentative detection of He i 6678 emission is made near primary minimum, but not at other phases. Finally, projected emission from hot dust in and around V367 Cyg is more or less symmetric and extends over 28″, or 0.09 pc at the distance of the system; V367 Cyg is thus expelling matter into a large volume of the surrounding space.

QS24. BIA-ALCL and Systemic ALCL Proliferate Differently in Response to Silicone Implant Shells Within a Three-dimensional Organotypic Model of the Breast Microenvironment

Purpose: Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a T-cell-derived lymphoma associated with device-based breast reconstruction, with a reported incidence anywhere between 1/1,000 and 1/30,000. As of October 2021, 1158 BIA-ALCL cases were reported with 35 deaths worldwide and in nearly every case, patients had a textured device at some point in time. Despite the increasing awareness and the high correlation with textured implants, the etiopathogenesis of BIA-ALCL remains largely unknown. We have developed a tissue-engineered biomimetic platform composed of patient-derived breast tissue derivatives that mimics the breast microenvironment to interrogate the role of the silicone shell in altering the behavior of normal and malignant T cell lines. Methods: AbbVie Biocell textured and smooth breast implant shells were shaped to line 96-well plates. Patient-derived breast tissue from mammaplasty procedures was digested into cellular components of adipocytes, stromal vascular fraction, and epithelial duct organoids. The breast tissue components were embedded in 0.3% type I collagen along with BIA-ALCL cell line IL89 and systemic ALCL cell line SUPM2 (200,000 cells/mL) and placed into 96-well plates with and without implant shell lining. Other experimental groups included IL89 and SUPM2 cultured within either a type I collagen ECM alone or low serum feeding media alone with or without implant shell lining. Low serum feeding media (0.5% BSA) was applied in all the groups to limit the additional effect of growth factors on cell proliferation. Imaging was performed every two days for ten days using confocal microscopy. Cell proliferation was quantified and analyzed using ImageJ and MetaMorph software. Results: IL89 cultured in low serum feeding media proliferated moderately over 10 days with no significant difference between groups. However, IL89 embedded in 3D-collagen appeared to have limited proliferation and even decreased over 10 days regardless of well lining. Notably, IL89 cultured within the biomimetic platform survived and even proliferated, of which cells exposed to this platform and a textured implant shell increased significantly (21.5%) when compared to those exposed to no implant shell (3.7%) (p<0.05). SUPM2 exposed to low serum media and no implant appeared to have an increased rate of proliferation (p>0.05). In collagen only, SUPM2 with all different implant shell linings stabilized or moderately proliferated with significant increases in textured and smooth groups when compared to no implant. In the biomimetic platform, SUPM2 had a higher rate of proliferation when compared to collagen only, which was not significant between groups. Conclusion: When cultured in a 3D breast biomimetic platform, BIA-ALCL cells proliferate within a simulated breast microenvironment even without the addition of growth factors, while limited or decreased proliferation is seen when cultured in the same conditions without such cellular components. We have shown a difference in the cell proliferation trends that occur when different ALCL lines are cultured in 2-dimensions (media only) versus 3-dimensions (collagen embedded), emphasizing the physiologic relevance of our 3-dimensional model. These data demonstrate the importance of recapitulating the cellular microenvironment ex vivo to elicit pathologic in vivo cell behaviors that do not occur under standard culture conditions.

Observation of chemical speciation on L X-ray emission spectra for gadolinium (III) materials

The proposed effort comprehends an extensive learning of the Ll, Lα2 and Lα1ƞ X-ray emission lines of selected gadolinium materials, viz., Gd pure, GdCl3, GdF3, Gd2O3 and Gd2S3O12 by utilizing the encroachment in test-bed based wavelength-dispersive spectrometer. The examination of the energy shifts on the L shell peaks of elected Gd targets has been summarized in the current assessment which involves the proper understanding of the physical fundamental parameters and ligands effects. According to our investigation, no experimental and theoretical data associated to the Ll, Lα2 and Lα1ƞ shell lines for Gd targets was conveyed previously. The obtained measured data reveals that the L shell lines emitted from different Gd targets exhibits the energy shifts of ~ (0.78–5.93) eV comparative to the Gd pure. Furthermore, the good agreement between the measured and theoretical data of radiative transition probabilities for L3M transitions and intensity ratio (I)Ll/Lαη values signifies the prospect of wide utilization of wavelength-dispersive spectrometer for other lanthanide materials. The promising correlation between the bond length, effective charge, intensity ratio and energy shifts for Gd L shell lines in Gd targets are also studied in the current article.

Measurement of Lysosome Positioning by Shell Analysis and Line Scan.

Lysosomes are membrane-bound organelles that degrade diverse biomolecules and regulate a multitude of other essential processes including cell growth and metabolism, signaling, plasmamembrane repair and infection. Such diverse functions of lysosomes are highly coordinated in space and time and are therefore tightly coupled to the directional transport of the organelles within the cytoplasm. Thus, robust quantitative assessments of lysosome positioning within the cell provide a valuable tool for researchers interested in understanding these multifunctional organelles. Here, we present point-by-point methodology to measure lysosome positioning by two straight forward and widely used techniques: shell analysis and line scan.

Genetic diversity in a genetically improved line of the Pacific oyster Crassostrea gigas with orange shell based on microsatellites and mtDNA data

The shell color is of interest to the shellfish industry and has been regarded as a target trait for a better commercial value. Based on an inbred variant line of the Pacific oyster Crassostrea gigas with orange shell obtained previously, a genetically improved orange-shell line was formed through hybridization and subsequent mass selection. In the present study, the genetic diversity among the base population (G0) and two successive mass-selected generations of the improved orange-shell line of C. gigas (G1 and G2) were assessed by both 15 microsatellites and mitochondrial cytochrome oxidase I sequences (mtCOI) compared to four outbred populations and three progenitor selected strains. The microsatellite results showed that the genetic variation over two generations of mass selection were maintained since no significant reduction in average number of alleles (Nα: 4.87–5.40), expected heterozygosity (He: 0.59–0.61) and expected heterozygosity (Ho: 0.48–0.54) compared with those of G0. The number of different alleles in the generations of improved orange-shell line ranged from 73 to 81 alleles, which was approximate 55–64% less than the 176–204 alleles found in the oysters from wild populations. The Nα in G0-G2 were obviously higher than that of the inbred orange-shell line without improvement. The differences in alleles in the improved orange-shell line compared to four wild populations is likely due to small broodstock size resulting in genetic drift over successive generations. Effective population size of G1 and G2 calculated by linkage disequilibrium methods was 63.2 and 89.8, respectively. On a population level, pairwise FST value (FST: 0.14–0.21) along with AMOVA analysis indicated medium to high genetic differentiation between the improved orange-shell line and outbred populations and progenitor selected strains. Overall, the results of microsatellite suggested that the genetic diversity of the improved orange shell line was not affected greatly by mass selection during the process of improvement. This study provides insight into utilization of shell color variants and future genetic improvement through selective breeding in aquaculture.

The A-shell star ϕ Leo revisited: its photospheric and circumstellar spectra

Context. We previously suggested that variable red- and blueshifted absorption features observed in the Ca II K line towards the A-type shell star ϕ Leo are likely due to solid, comet-like bodies in the circumstellar (CS) environment. Aims. Our aim is to expand our observational study of ϕ Leo to other characteristic spectral lines of A-type photospheres as well as to lines arising in their CS shells. Methods. We obtained more than 500 high-resolution optical spectra collected at different telescopes over 37 nights in several observing runs from December 2015 to January 2019. Consecutive time-series spectra were taken, covering intervals of up to ~9 h on some nights. We analysed some photospheric lines, in particular Ca I 4226 Å and Mg II 4481 Å, as well as the circumstellar shell lines Ca II H and K, the Ca II IR triplet, Fe II 4924, 5018, and 5169 Å, Ti II 3685, 3759, and 3761 Å, and the Balmer lines Hα and Hβ. Results. Our observational study reveals that ϕ Leo is a variable δ Scuti star whose spectra show remarkable dumps and bumps superimposed on the photospheric line profiles, which vary in strength and sharpness, propagate from blue- to more redshifted radial velocities, and persist for a few hours. Similarly to other δ Scuti stars, these features are likely produced by non-radial pulsations. At the same time, all shell lines present emission at ~3 km s−1 centred at the core of the CS features, and two variable absorption minima at both sides of the emission; those absorption minima occur at almost the same velocity for each line, that is, no apparent dynamical evolution is observed. The variations observed in the Ca II H and K, Fe II, and Ti II lines occur on a range of timescales from minutes to days and between observing runs, but without any clear correlation or recognisable temporal pattern among the different lines. In the case of Hα, the CS contribution is also variable in just one of the observing runs. Conclusions. We suggest that ϕ Leo is a rapidly rotating δ Scuti star surrounded by a variable, (nearly) edge-on CS disk possibly re-supplied by the δ Scuti pulsations. The behaviour of the CS shell lines is reminiscent of that of rapidly rotating Be shell stars with an edge-on CS disk, and is clear evidence that the variations observed in the CS features of ϕ Leo are highly unlikely to be produced by exocomets. In addition, the observational results presented in this work, together with some recent results concerning the shell star HR 10, highlight the need for critical revision of the Ca II K features, which have been attributed to exocomets in other shell stars.

Crossbreeding of three different shell color lines in the Pacific oyster reveals high heterosis for survival but low heterosis for growth

Heterosis is important for improving productive traits in aquaculture, but the heterosis between selected lines remains unclear in bivalve molluscs. Here, a diallel crosses among black shell (B, 7th generation), white shell (W, 7th generation) and orange shell (O, 6th generation) lines of the Pacific oyster were performed to examine the potential for exploiting heterosis of productive traits by crossbreeding of selected lines. Heterosis and combining abilities for growth and survival of 27 full-sib families were analyzed at both larval and juvenile stages, of which the juvenile stage was examined at two environments (Rongcheng and Rushan) for 10 months. The variance of specific combining ability accounts for the majority of the total variance for larval and juvenile survival and juvenile growth, which revealed the importance of non-additive genetic effects (heterosis) among these lines. Moreover, all reciprocal hybrids showed low or no heterosis for growth at both larval and juvenile stages, but a high heterosis for larval survival. This finding suggested that inter-line crossbreeding can be applied to improve the larval survival in hatcheries. Furthermore, four of six hybrid crosses showed positive HPH in Rushan but negative HPH in Rongcheng. The higher HPH at Rushan suggested that inter-line crossbreeding in C. gigas has more application value in Rushan. In addition, the survival of both black shell and white shell lines have been improved by crossing with the orange shell line. Especially, the hybrid cross WO (W♀ × O♂) can improve the survival rate of purebred WW by nearly 130% at larval stage and nearly 40% at juvenile stage. Overall, this study reveals the high heterosis for survival among selected lines in the Pacific oyster, and will be helpful for the utilization of non-additive genetic effects among existing selected lines in bivalves.

Response to selection for growth in the second generation of two shell color lines of the bay scallop Argopecten irradians

The bay scallop Argopecten irradians is one of the most commercially important aquaculture species in China. A. irradians with two different shell color (red and black) from cultured stocks in China were used to establish two mass-selected strains (red shell line and black shell line) for fast growth, and a positive response to selection for fast growth was observed in the first generations. To determine whether continuous progress can be achieved by selection for growth, we evaluated response to selection for the second generations of the two shell color lines. At grow-out stage, a genetic gain of 13.23%–15.71%, selection response of 1.62–1.71 and realized heritability of 0.43–0.45 for shell length were observed in the selective breeding strains after two generations of selection. The current response to selection for growth obtained in the second-generation selection strains suggests that a large amount of genetic variance still remains in the selected strains and there is a potential for sustained genetic improvement in growth-related traits in these strains through selective breeding. The results obtained in this study provides important information for future breeding programs for A. irradians.

Mass Selection for Growth Improvement in Black Shell Line of Pacific Oyster Crassostrea gigas

The Pacific oyster, Crassostrea gigas, naturally distributing along the coast of northwest Pacific, is one of the most important bivalve species due to its high economic value and fecundity. In China, we have initiated a selective breeding program on both shell color and growth rate of C. gigas since 2010. A black shell line was obtained through four-generation family selection. In this study, mass selection for growth improvement was conducted in the sixth generation and seventh generation of black shell lines. To assess the progress of potential genetic improvement, the progeny of two generations of black shell lines were selected to evaluate their shell heights via a 450-day farming experiment. As the results, after growing for 450 days, the sixth generation and seventh generation of selected lines were 9.03% and 11.42% larger than the control lines, respectively. During the grow-out stage, the genetic gain of two generations was 8.82%±0.18% and 11.54%±0.43%, respectively; and the corresponding realized heritability was 0.45± 0.04 and 0.41 ±0.04, respectively. These results indicated that the mass selection for shell height achieved steady progress in the two generations of C. gigas.

A HEADRACE TUNNEL RECONSTRUCTION IN TURKEY

The operation of a hydro power project in North Turkey started in 2015, included the 12km long headrace tunnel. An 8km long lower tunnel section was excavated by double shield TBM technology with 8.7m ID. Due to problems with the mechanised excavation, a 4km long upper tunnel section was excavated conventionally by the Drill and Blast method with single shell lining generated from fibre reinforced sprayed concrete and rock bolts. Significant operational problems were observed in September 2016. The flooded tunnel was investigated by underwater Remotely Operated Vehicle which indicated significant collapses. Operation of the power station had to be stopped and water from a supply dam at the headrace tunnel inlet had to be discharged to enable dewatering and inspection of the tunnel. Consequent investigation revealed three major collapses and a considerable variety of other damages in the D&amp;amp;B section of the tunnel. Repair and strengthening of the tunnel was completed in October 2017.

Application of Composite Shell Lining for Qingdao Metro Xizhen Station

Combined with the composite shell lining design of Xizhen station of Qingdao Metro line1, application of composite shell lining in Qingdao Metro station is introduced. The composite shell lining technology is set forth from such aspects as Mix design, characteristic research, construction technology and quality control, test standard and construction matters of structure fibre concrete, as well as good result is obtained in the practice. This paper provides some reference for the design and construction of similar tunnels.

Rapid and Cyclable Morphology Transition of High-χ Block Copolymers via Solvent Vapor-Immersion Annealing for Nanoscale Lithography

The self-assembly of block copolymers (BCPs) has attracted considerable attention because it can effectively generate highly ordered nanostructures through a simple and cost-effective process. However, in BCP annealing systems, there remain several challenges and issues that must be resolved to achieve more rapid and tunable pattern formation of BCPs with a high Flory–Huggins parameter (χ) for next-generation lithography applications. Here, we introduce a useful annealing technique to induce a rapid morphological transition of sphere-forming poly(styrene-b-dimethylsiloxane) (PS-b-PDMS) BCPs by employing multistep solvent vapor annealing (MSVA) and a combined annealing process of solvent vapor annealing (SVA) and immersion annealing (IA). We successfully obtained well-ordered sub-20 nm line, dot, core–shell dot, and core–shell line structures with a short annealing time (<25 min) based on the synergetic effects of the combined annealing method which provides both the fast self-assembly kinetics and a wide range of pattern geometries. Furthermore, we demonstrate how the repeated process of SVA and IA affects the morphological stability of self-assembled BCPs, showing highly ordered solid and core–shell BCP nanostructures even after ten cycles of the repeated annealing process. We expect that these results will provide a new guideline to manipulate diverse BCP nanostructures effectively for nanodevice fabrication by combining various annealing methods.

The Design for 3000 m3 Blast Furnace

This design mainly includes the design of blast furnace type, the design of furnace lining, the selection of blast furnace cooling equipment and the design of tuyere and iron outlet. The main body of blast furnace is divided into five parts: throat, body, waist, chamber and chamber. The cross section of the blast furnace is the circular ironmaking shaft furnace, the steel plate is used as the furnace shell, and the furnace shell lining is firebrick lining. At the same time, the design of blast furnace with small environmental pollution, the furnace body structure and auxiliary system must meet high temperature resistance, high pressure resistance, corrosion resistance, good sealing performance, reliable work and long service life to achieve high quality, low cost, high output, long life of furnace life. Good quality, high output, low consumption and other requirements. In the design of blast furnace body, the size of blast furnace body is calculated according to technical and economic indexes, and the furnace shape is determined. Reasonable allocation of firebrick, reasonable choice of blast furnace cooling equipment, reasonable design of tuyere and iron outlet.

Genetic diversity and effective population size in successive mass selected generations of black shell strain Pacific oyster (Crassostrea gigas) based on microsatellites and mtDNA data

The Pacific oyster (Crassostrea gigas) is one of the highly fecund marine aquaculture species and has a large variance in reproductive success, these characteristics can result in loss of genetic diversity and inbreeding especially when conducting mass selection. In the current study, we investigated the level of genetic diversity and effective population size over three successive mass-selected generations in the black shell strain of C. gigas assessed by 11 microsatellites as well as mitochondrial COI region. The results showed that the genetic variation over three generations were maintained since no detectable depression of expected heterozygosity (He = 0.647–0.681), number of alleles (N = 5.6–6.0) and haplotypes (Nh = 2). The difference in alleles and haplotypes number between the base population (BP) and three mass selective generations (M5-M7) could be mainly due to the loss during preceding family selection process. Pair-wise FST values along with AMOVA analysis from both markers indicated unremarkable differentiation within each generation including BP. There was no deleterious effect on genetic diversity and population structure for mass selected generations imposed by our artificial breeding practice. The Neb estimation for M5, M6 and M7 was 29.8, 40.7 and 52.7, respectively. The different number of broodstocks used for each generation implied that using a balanced sex ratio and large size of broodstock as well as low selection pressure would help to increase the effective population size and avoid high level of inbreeding. The estimated linkage disequilibrium-based effective breeders size (Neb) was significantly lower than sex-ratio correction effective population size (Ne), which indicated high variance in family contribution. It is suggested during mass spawning to simply undertake several mini-spawn groups and then pool the embryos to produce next generation, which can be a hedge to the high variance in reproductive success, thus, the loss of effective populations size and diversity. Other practical strategies against the loss of genetic diversity were also discussed, however, it remains to be investigated how diverse selection and follow-up procedures will benefit retaining genetic variability. This study will provide an insight into the level of genetic diversity and effective population size within mass-selected black shell line and enable a better understanding of how efficient current breeding practices are at maintaining genetic variation. This information can be applied for future selective breeding program and in the design of suitable management guidelines for sustainable breeding of C. gigas.

Development of a water‐permeable annular gap fill for single‐shell drained segmental linings

AbstractNowadays, tunnels with single‐shell segmental lining are often constructed pressure‐tight using gaskets. The economic application limit of this construction type is about 50 metres head of water. If the water pressure exceeds this value, considerably more complex – and thus more expensive – two‐shell construction with an additional drainage layer between the inner and the outer lining is required. To extend the field of application of mechanized tunnelling with single shell lining in mid‐mountain formations, an innovative approach was developed based on the application of a drainage layer in the annular gap fill with a water permeability kF &gt;10–4 m/s. The basic idea of the newly developed water‐permeable material for annular gap grouting is the use of a foam generator without a disturbing body, which foams the cement suspension in a defined way with sufficient compressive strength. Complex interrelations of material, process engineering and construction had to be considered comprehensively. The overall suitability of the developed process has been demonstrated in an extensive experimental program including field tests. The present paper focuses on the development of the construction material.

The Remarkable Be+sdOB Binary HD 55606. I. Orbital and Stellar Parameters*

Abstract Prompted by peculiar spectroscopic variability observed in SDSS/APOGEE H-band spectra, we monitored the Be star HD 55606 using optical spectroscopy and found that it is an exotic double-lined spectroscopic binary (SB2) consisting of a Be star and a hot, compact companion that is probably an OB subdwarf (sdOB) star. The motion of the sdOB star is traced by its impact on the strong He i lines, observed as radial velocity (V r ) variable, double-peaked emission profiles with narrow central absorption cores. Weak He ii 4686 Å absorption associated with the companion star is detected in most spectra. Use of the emission peaks of low-ionization emission lines to trace the Be star V r and the He i lines to trace the companion star V r yields a circular orbital solution with a 93.8 day period and masses of M Be = 6.2 M ⊙ and M sdOB = 0.9 M ⊙ in the case of i = 80°. HD 55606 exhibits a variety of phase-locked variability, including the development of shell lines twice per orbit. The shell phases coincide with variation in the double emission peak separations, and both forms of variability are likely caused by a two-armed spiral density perturbation in the Be disk. The intensity ratios of the double emission peaks are also phase-locked, possibly indicating heating by the sdOB star of the side of the Be disk facing it. HD 55606 is a new member of the growing sample of Be+sdOB binaries, in which the Be star’s rapid rotation and ability to form a disk can be attributed to past mass-transfer.

Numerical calibration of mechanical behaviour of composite shell tunnel linings

Composite shell linings consist of primary and secondary sprayed concrete linings separated by a layer of spray-applied waterproofing membrane. In order to design such a lining configuration, a calibrated numerical simulation approach is needed and the impact of interface properties on the composite mechanical behaviour should be understood.A programme of laboratory tests was carried out on beam samples cut from composite shell test panels and subjected to four-point bending under short-term loading. A range of membrane thicknesses and substrate roughness were compared and composite mechanical behaviour quantification methods developed. The behaviour of composite beams was understood and the strain distribution across composite lining cross-section was identified.A numerical model by the finite difference method was then set up for the beams and verified against the test data. With interface stiffnesses obtained from previous element tests, the composite beam model is capable of predicting the strain distribution across the cross-section and real behaviour of composite beam members to within an acceptable level of accuracy taking into account variations arising from workmanship. Sensitivity studies were carried out to understand the impact of interface properties and membrane interface position on the degree of composite action.