Shell Diameter Research Articles

Recruitment of the endangered limpet Patella ferruginea in the Chafarinas Islands (SW Mediterranean)

AbstractThe recruitment of the endangered limpet Patella ferruginea in the Chafarinas Islands (SW Mediterranean) was studied over a 17-year period (1999‒2015). A total of 8115 recruits <20 mm in maximum diameter were counted in 95 transect censuses sampled during the study period. The presence of recruits began at the end of winter or beginning of spring (March‒April), when they reached a maximum shell diameter (MD) of at least 4 mm, with a peak in abundance occurring in spring. Smaller recruits were found on the lower midlittoral on the fringe of the vermetid gastropod Dendropoma lebeche and the crustose coralline algae Neogoniolithon brassica-florida, which suggests that settlement occurs at this shore level. Recruits reach 12‒27 mm at the end of their first year of life. A regular recruitment was detected for all studied years, with an average of 11.71 recruits m−1 across the study period. However, recruitment exhibited high interannual variability and did not occur evenly along the coastline of the islands. Higher recruitment was observed in 2001, 2011 and 2012, with a maximum density of 69.07 recruits m−1 in one transect in 2012. The density of recruits decreased in summer. No significant correlation was found between the density of recruits and adults. Between 1999‒2010, 29.29% of recruits were ‘phoretic’ on the shell of adults (1.81 recruits per host on average). Recruits climbed on to adults sometime after settlement, thus we suggest that ‘phoresy’ could favour the survival of young limpets instead of being due to selective settlement on adults. To improve and standardize recruitment monitoring in future studies, we propose that recruits are considered as those specimens <20 mm in MD and that recruitment censuses are carried out in spring, with additional censuses after summer to detect juvenile mortality. Additionally, we propose that 1 mm interval size classes are used for growth studies based on size‒frequency analyses.

Thermo-ecological optimization of shell and tube heat exchanger

Shell and Tube Heat Exchangers are kind of equipment which are used in practical applications that it has to deliver optimum performance in terms of high efficiency, high heat transfer rate, less losses, low cost, etc. In the heat exchanger “Entransy” determines how efficient the system is to deliver the work and transfer the heat. Likewise, “Ecological function” defines how effectively it affects the environment. In this paper, the shell and tube heat exchanger is studied for an ecological and total cost viewpoint. The effect of various geometric parameters such as tube diameter, shell diameter, pitch, etc. on the ecological and total cost is studied and discussed. By performing the parametric analysis, optimum value of each variable is obtained from a predefined range and at that value highest ecological function value and lowest cost values are obtained. The main motive of this research study is to analyze the effect of geometric variables on the cost as well as output of the heat exchanger. In that way the proposed study helps to identify the important design variable of the heat exchanger.

Research on the molluscicidal activity and molecular mechanisms of arecoline against Pomacea canaliculata

Pomacea canaliculata, as an invasive snail in China, can adversely affect agricultural crop yields, ecological environment, and human health. In this paper, we studied the molluscicidal activity and mechanisms of arecoline against P. canaliculata. The molluscicidal activity tests showed that arecoline exhibits strong toxicity against P. canaliculata, and the LC50 value (72 h) was 1.05 mg/L (15 ± 2 mm shell diameter). Additionally, Molluscicidal toxicity were negatively correlated with the size of snails. Snails (25 ± 2 mm shell diameter) were choosed for mechanisms research and the result of microstructure and biochemistry showed that arecoline (4 mg/L, 20 ℃) had strong toxic effect on the gill, and the main signs were the loss of cilia in the gill filaments. Moreover, arecoline significantly decreased the oxygen consumption rate, ammonia excretion rate and inhibited acetylcholinesterase (AChE). Then, the changes in protein expression were studied by iTRAQ, and 526 downregulated proteins were found. Among these, cilia and flagella-associated 157-like (PcCFP) and rootletin-like (PcRoo) were selected as candidate target proteins through bioinformatics analysis, and then RNA interference (RNAi) was adopted to verify the function of PcCFP and PcRoo. The results showed that after arecoline treated, the mortality and the cilia shedding rate of PcRoo RNAi treated group was significantly lower than control group. The above results indicate that arecoline can bind well with protein PcRoo, and then leads to the drop of gill cilia, affect respiratory metabolism, accelerate its entry into hemolymph, inhibit AChE and finally leads to the death of P. canaliculata.

SEASONAL OCCURRENCE OF NEOECHINORHYNCHUS EMYDIS (PHYLUM: ACANTHOCEPHALA) IN THE FRESHWATER SNAIL, PLANORBELLA CF. P. TRIVOLVIS, FROM OKLAHOMA.

The acanthocephalan Neoechinorhynchus emydis has a complex life cycle and infects turtle, ostracod, and snail hosts. However, little information is available on the seasonal distribution or the effects of N. emydis on freshwater snail hosts. To address this, we examined the seasonal distribution and melanization of acanthocephalans in Planorbella cf. Planorbella trivolvis snails from a single location in north-central Oklahoma. Seasonally, prevalence of N. emydis was 0% during the winter, increased to 50% during the summer, and declined to 17% in the fall. Mean abundance exhibited more variation but generally followed a similar pattern as prevalence. More important, all acanthocephalans located within the head/foot region of snail hosts contained melaninlike pigment surrounding each worm, suggesting that snails were mounting an immunological reaction to infections with N. emydis. Snail shell diameter was greatest during the fall and decreased during the winter, indicating that larger or older snails were dying during the winter. However, because field-collected snails were commonly infected with trematodes, and snail size varied significantly with season, it was unclear whether the observed seasonal dynamics of acanthocephalan infections were a result of snail mortality resulting from snail age, parasitic infections, or a combination of factors. To control for these factors, we exposed laboratory-reared Planorbella cf. P. trivolvis snails to naturally infected ostracods in field cages for 5-wk intervals during the winter, spring, and summer. Data from snail-cage infections were consistent with the seasonal field survey such that N. emydis infections were highest in the summer (20%) and lowest (0%) in the winter, suggesting that snails were not ingesting infected ostracods during the winter. However, fewer of our laboratory-reared snails survived in field cages during winter than during spring and summer, suggesting that snails may die more often during harsh winter conditions. Finally, we conducted a laboratory survival experiment by testing the life span and egg production of field-collected snails of various sizes that were naturally infected with acanthocephalans or trematodes or both. Our snail-survival experiment indicated that snail size but not infection status with acanthocephalans or trematodes affected snail survival, with larger snails surviving a shorter amount of time than smaller snails. In addition, snails infected with trematodes laid significantly fewer eggs compared with uninfected snails or snails infected with acanthocephalans. However, we found no significant difference in the number of eggs laid by acanthocephalan-infected and uninfected snails. Although other abiotic factors still need evaluation, we suggest that the occurrence of acanthocephalans in snails throughout the year may be partially influenced by the abundance of infected ostracods that snails may be ingesting and snail population fluctuations during the year.

Multi-objective optimization of a phase change material-based shell-and-tube heat exchanger for cold thermal energy storage: experiments and numerical modeling

• PCM-based cold thermal energy storage is numerically and experimentally analysed. • The experimental outcomes show room for optimization in the PCM discharging phase. • Charging/discharging time and heat transfer area/melting difference are optimized. • Multi-objective genetic algorithm allows to exploit up to 72% PCM latent heat. • This optimal solution implies a 69% increase in minimum heat transfer area. In recent years, significantly increasing demand for air conditioning systems has led to higher power consumption during on-peak hours. If optimized, latent heat thermal storage for chiller systems – thanks to its high storage density and compact structure – can reduce installed cooling capacity and allow the chiller to operate more continuously. Starting from the existing design, this work presents a multi-objective optimization framework to improve the storage performance of a phase change material (PCM)-based shell-and-tube heat exchanger. To address this issue – based on experimental data – a 2D axial-symmetric transient numerical model is first developed. To investigate the overall performance of the system – depending on geometrical features and chiller operating conditions – a parametric analysis is performed. Then, by coupling the numerical model developed in COMSOL Multiphysics environment with MATLAB, the system performance is optimized through the genetic algorithm (GA), i.e., minimizing PCM charging/discharging time, by varying the chiller operating conditions. The optimal solution is achieved under a water mass flow rate of 0.095 kg/s, implying a reduction in the inlet temperature of 1.25 °C with respect to the reference case. Results are further validated through experimental tests and discussed looking at the PCM melting and solidification processes for better exploitation of this storage technique. As the main outcome of the model optimization on user’s demand, the maximum amount of PCM that can be fully exploited is equal to 40 % of the initial one. Therefore, based on this value, a further optimization step by GA is performed to define the minimum heat transfer area, resulting in a shell diameter reduction of 12 cm to exploit 72 % of the PCM potential.

Combustion characteristics and detailed simulations of surrogates for a Tier II gasoline certification fuel

An experimental and numerical study of combustion of a gasoline certification fuel (‘indolene’), and four (S4) and five (S5) component surrogates for it, is reported for the configurations of an isolated droplet burning with near spherical symmetry in the standard atmosphere, and a single cylinder engine designed for advanced compression ignition of pre-vaporized fuel. The intent was to compare performance of the surrogate for these different combustion configurations and to assess the broader applicability of the kinetic mechanism and property database for the simulations. A kinetic mechanism comprised of 297 species and 16,797 reactions was used in the simulations that included soot formation and evolution, and accounted for unsteady transport, liquid diffusion inside the droplet, radiative heat transfer, and variable properties. The droplet data showed a clear preference for the S5 surrogate in terms of burning rate. The simulations showed generally very good agreement with measured droplet, flame, and soot shell diameters. Measurements of combustion timing, in-cylinder pressure, and mass-averaged gas temperature were also well predicted with a slight preference for the S5 surrogate. Preferential vaporization was not evidenced from the evolution of droplet diameter but was clearly revealed in simulations of the evolution of mixture fractions inside the droplets. The influence of initial droplet diameter (Do) on droplet burning was strong, with S5 burning rates decreasing with increasing Do due to increasing radiation losses from the flame. Flame extinction was predicted for Do =3.0 mm as a radiative loss mechanism but not predicted for smaller Do for the conditions of the simulations.

Evaluation of the Reproductive Performance, Body Proportions, Nutritional Value, and Biochemical Parameters of Achatina achatina

To assess the effect of energy levels on the reproductive performance of African Land Snails, ninety young snails of one month of age, weighing between 1 and 1.5 g, of shell length between 15.5 and 23.85 mm and shell diameter between 12.60 and 16.85 mm and free from wounds or shell defects were divided into 3 groups of 5 snails each and 6 replicates in cages equipped with feeders and drinking troughs. Each treatment was randomly assignedto one of the experimental feeds with variable energy levels (2600, 2800, and 3000 kcal/kg) in addition to pawpaw leaves as a staple feed. The cultured substrates were watered daily, and the animals were monitored for a period of 24 months. The results showed that the shortest ages of onset of maturity as well as the highest number of spawns per treatment were observed in snails receiving 2600 kcal/kg of energy in the feed compared to other treatments. The highest egg morphometric and fertility characteristics were found in animals fed the highest energy level of the feed. The highest protein level in the hemolymph was observed in snails given 3000 kcal/kg energy of the feed while the lowest cholesterol level was observed in animals receiving the same treatment. The highest total meat and gonad weight were observed in animals receiving 2800 kcal/kg energy in the feed compared to other treatments. The levels of dry and organic matter, protein, and fat in the ash increased with the energy level of the diet. Animals that received 2800 kcal/kg energy in the diet recorded a significantly lower calcium level in the flesh compared to the other two treatments. On the other hand, the percentage of phosphorus increased significantly with the energy level of the diet. In conclusion, the 2600 kcal/kg energy level can be retained in the feed of adult snails.

Express method for measuring the refractive index of transparent fibres

An express method for measuring the refractive index, which is one of the main optical parameters of transparent fibres, is suggested. The method uses focusing properties of a cylindrical lens, which such a fibre is. The possibility to accurately measure such characteristics of optical fibres as the shell and core diameters, numerical aperture, refractive index profile, loss, and dispersion is equally important for fibre manufacturers and designers of optical communication systems who should choose the fibre that meets their requirements best. Almost all measurement methods use the refraction of light rays at the interface between the media. To do this, one should make samples of given shape and size, which are individual for each measuring instrument. The suggested method takes into account the fact that when light strikes upon a refractive cylinder (glass rod, fibreglass), the focusing occurs perpendicular to its axis with a focal region where light rays converge. Behind this region, the rays diverge again. The position of the focal region is determined by the refractive index of the cylinder. It can be inside the cylinder, outside it, or on the surface of the cylinder. During the observation of the fibre using a microscope, one can see that the light, which has passed through the fibre, forms a bright band on its backside against a dark background. The bandwidth depends on the refractive index of the fibre. The calculations using the methods of geometric optics were carried out. These methods may be applied over a wide range of fibre diameters. Using strict formulas of diffraction theory, the distribution of radiation energy in the fibre and its vicinity was calculated. A digital analysis of the resulting pattern was carried out. The results of the analysis coincided with the results obtained using the methods of geometric optics. An algorithm for determining the refractive index was worked out. The measurements of the refractive indices of artificial and natural fibres like fibreglass, webs and human hair (blonde-haired person, brown-haired person, grey hair) were provided.

Cd3P2/Zn3P2 Core-Shell Nanocrystals: Synthesis and Optical Properties.

II–V semiconductor nanocrystals such as Cd3P2 and Zn3P2 have enormous potential as materials in next-generation optoelectronic devices requiring active optical properties across the visible and infrared range. To date, this potential has been unfulfilled due to their inherent instability with respect to air and moisture. Core-shell system Cd3P2/Zn3P2 is synthesized and studied from structural (morphology, crystallinity, shell diameter), chemical (composition of core, shell, and ligand sphere), and optical perspectives (absorbance, emission-steady state and time resolved, quantum yield, and air stability). The improvements achieved by coating with Zn3P2 are likely due to its identical crystal structure to Cd3P2 (tetragonal), highlighting the key role crystallographic concerns play in creating cutting edge core-shell NCs.

The Other Dimension-Tuning Hole Extraction via Nanorod Width.

Solar-to-hydrogen generation is a promising approach to generate clean and renewable fuel. Nanohybrid structures such as CdSe@CdS-Pt nanorods were found favorable for this task (attaining 100% photon-to-hydrogen production efficiency); yet the rods cannot support overall water splitting. The key limitation seems to be the rate of hole extraction from the semiconductor, jeopardizing both activity and stability. It is suggested that hole extraction might be improved via tuning the rod’s dimensions, specifically the width of the CdS shell around the CdSe seed in which the holes reside. In this contribution, we successfully attain atomic-scale control over the width of CdSe@CdS nanorods, which enables us to verify this hypothesis and explore the intricate influence of shell diameter over hole quenching and photocatalytic activity towards H2 production. A non-monotonic effect of the rod’s diameter is revealed, and the underlying mechanism for this observation is discussed, alongside implications towards the future design of nanoscale photocatalysts.

Modeling of core-shell magneto-electric nanoparticles for biomedical applications: Effect of composition, dimension, and magnetic field features on magnetoelectric response.

The recent development of core-shell nanoparticles which combine strain coupled magnetostrictive and piezoelectric phases, has attracted a lot of attention due to their ability to yield strong magnetoelectric effect even at room temperature, thus making them a promising tool to enable biomedical applications. To fully exploit their potentialities and to adapt their use to in vivo applications, this study analyzes, through a numerical approach, their magnetoelectric behavior, shortly quantified by the magnetoelectric coupling coefficient (αME), thus providing an important milestone for the characterization of the magnetoelectric effect at the nanoscale. In view of recent evidence showing that αME is strongly affected by both the applied magnetic field DC bias and AC frequency, this study implements a nonlinear model, based on magnetic hysteresis, to describe the responses of two different core-shell nanoparticles to various magnetic field excitation stimuli. The proposed model is also used to evaluate to which extent realistic variables such as core diameter and shell thickness affect the electric output. Results prove that αME of 80 nm cobalt ferrite-barium titanate (CFO-BTO) nanoparticles with a 60:40 ratio is equal to about 0.28 V/cm∙Oe corresponding to electric fields up to about 1000 V/cm when a strong DC bias is applied. However, the same electric output can be obtained even in absence of DC field with very low AC fields, by exploiting the hysteretic characteristics of the same composites. The analysis of core and shell dimension is as such to indicate that, to maximize αME, larger core diameter and thinner shell nanoparticles should be preferred. These results, taken together, suggest that it is possible to tune magnetoelectric nanoparticles electric responses by controlling their composition and their size, thus opening the opportunity to adapt their structure on the specific application to pursue.

Macro Land Snail Diversity and Community Assemblage in Selected Forest Fragments of Leyte Island, Philippines

The diversity of land snails in Leyte Island has not been examined over the past few years. To address this, a survey of macro land snails (> 5 mm in shell height and diameter) in selected forest fragments of Leyte was conducted. A total of 120 quadrats (10 x 10 m) were set in three sampling sites (Inopacan, Baybay, and Maasin) that varies in area size – with Baybay being the largest fragment, followed by Inopacan and Maasin. From a total of 592 individuals, 22 macro land snail species and five families were identified. The macro land snail assemblage was dominated by endemic eupulmonates (Order Stylommatophora) and caenogastropods (Order Architaenioglossa). Among eupulmonates, Family Camaenidae had the most species (10), followed by Trochomorphidae and Achatinidae (two each), and Helicarionidae (one). For caenogastropods, all seven species were under Family Cyclophoridae. Cyclophorus appenidiculatus was the most abundant, representing 16.65% of the total number of individuals. Lissachatina fulica, an invasive land snail, was also documented in all sites. A β-dominated community assemblage was revealed by species accumulation curves with sampling efficiency using a completeness ratio of 1, which indicates a highly efficient sampling method. Detrended correspondence analysis indicated high similarity in species composition among study sites, with two unique species (Subulona cylindracea and Hypselostyla boholensis) recorded in Maasin and two incidental records (Obba bigonia and Helicobulinus sarcinosa). This study yielded 15 new records of macro land snail species during the sampling. There were five species (Hemiglypta semiglobosa, Amphidromus maculiferus, Leptopoma perlucidum, Chloritis leytensis, and Obba bigonia) that were documented on earlier records on the island, but 33 of the previously recorded macro land snail species were not encountered in the study. The community ecology patterns were also documented in the fragmented forests of Leyte, which is very important in local malacofaunal conservation and management.

Концептуальные проблемы организации рентабельной разработки и добычи железомарганцевых конкреций со дна Мирового океана

Object and purpose of research. The study is focused on problems of extraction of ferromanganese nodules from the bottom of the World Ocean. This extraction is still insignificant and amounts to no more than 2% of the value of ores mined on land, but its potential is disproportionately large. Of great interest is the deep-water zone of the Clarion- Clipperton faults, where one of the largest deposits of ferromanganese nodules has been registered. For many years, the development of deep-sea deposits of such nodules was considered a low-profit and complex process, but recently the position of researchers has been changing. To increase profitability, it is required to minimize the number of dives and, consequently, to have large-sized hull structures. Main results. To solve this problem, the design of the hull of the underwater vehicle according to the type of the so-called polyhull is proposed. Its main idea is related to the fact that for reinforced cylindrical shells of large diameter, the cylindrical shape of the body is not effective due to technological (in thickness) and strength limitations. The polyhull, whose diameter is not less than 20 m, contains at least 12 modules with a diameter of 2–4 m. The modules are connected by double stringers, web frames and transitional airlocks. The modules are intended to serve as an energy module, a high-pressure tank, an accommodation module, floats, a preparation and processing plant, a warehouse and a repair base for mining robotics, a rescue module, etc. The proposed design solutions can also be used to lift large-sized sunken objects. Conclusion. Research in this area is increasingly becoming the prerogative of governments, because, on the one hand, they require a large amount of capital investment, and, on the other hand, metals found in nodules are constantly becoming more expensive. The development of new technologies stimulates the technological development of the entire industry and opens up new prospects for the economic system.

Simulation of Shell and Helical Coil Heat Exchanger for Hot and Cold Fluid Flowing Fe2O3 Nanofluid with Water as Its Base by Using CFD

Abstract: Shell and Helical coils are eminent coiled tubes which have been used in diversity of solicitations e.g. heat recovery, air-conditioning and preservation schemes, chemical reactors and dairy practices. Shell and Helical coil heat exchanger is the recent improvement of heat exchangers, to accomplish the industrial demand. A shell and helical coil are necessary for various heat exchangers, nuclear reactors and in chemical engineering, for of large quantity of heat is conveying in a slight space with high heat transmission rates and slight habitation time distributions even it suffers through a disadvantage of larger pressure drop. The unbiased of this work is to cheered the pressure drop inside a shell and helical coil heat exchanger, heat transfer progression can be improved by increasing secondary flow inside the coil and this can be allow by appropriate blending of the fluid inside the helical coil. For this, my planned work on CFD to scrutinize the helical coil by using ANSYS 15. A 3D design of CAD model of helical coil of tube outer diameter (do) 16 mm, inner diameter of helical coil (di) 12 mm, pitch of 26.3mm, pitch coil dia. 86 mm, tube length of 235 mm, shell diameter is 110 mm and shell length is 215 mm, is generated by using ANSYS fluent 15.

Determining regularities of the stressed-strained state of flexible shell of the pneumatic spring made of polymeric material

Pneumatic springs make it possible to implement the «soft» characteristics of the suspension of vehicles, which provides comfortable conditions for passengers and reduces the dynamic load on the road surface. The issue of the strength of the flexible shells of pneumatic springs, which are made of rubber cord, remains relevant. Strains that stretch flexible shells, which arise in the process of movement, cause ruptures of rubber cord, thereby reducing their reliability. At present, there is a global tendency to replace rubber cord with polymeric materials. This paper reports a study of the strength of a two-sided flexible shell of the cylinder type under different operational modes of a pneumatic spring. The research was carried out using a finite-element method. The peculiarity of the pneumatic spring design is that the diameters of the bottoms and inter-corrugation ring are increased to the size of the outer diameter of the flexible shell in order to improve the stability and damping properties of the pneumatic suspension. The flexible pneumatic spring shell is made of polymeric material. It is proved that the stress in the material of the flexible shell increases in proportion to the air pressure in its cavity; their greatest values are observed in places where the flexible shell is fixed to the bottoms. When approaching the equator of the shell, they gradually decrease by an average of 20 % in both corrugations. The increase in the radius of the equator in both corrugations of the flexible shell did not exceed 20 mm. With a mutual transverse displacement of the bottoms by 40 mm and excessive air pressure of 0.5 and 1.0 MPa, the stress in the flexible shell material was 2.9 MPa and 5.9 MPa, respectively. This is almost five times less than the strength limit of the material for breaking (30 MPa). Thus, the selected parameters ensure the strength of the flexible pneumatic spring shell: it can be recommended for use on vehicles

ПЛАНУВАННЯ ЕКСПЕРИМЕНТАЛЬНИХ ДОСЛІДЖЕНЬ ЦИЛІНДРИЧНИХ НЕСУЧИХ ЕЛЕМЕНТІВ ОПОР БУДІВЕЛЬ ТА СПОРУД

A new construction of cylindrical load-bearings support of buildings is offered, that has an alternative reinforced concrete and with using of several different ways of indirect use. Shell is introduced for the view of the new construction sieved sheet, that is created from non-exit technology using imbibitions and extrusion of the steel sheet itself..
 For gaining the maximum amount of advantages and disadvantages from the introduced us reinforced concrete elements with mesh shell. The most efficient is method is a comprehensive research of introduced construction, as well as an already known researches of reinforced concrete with mesh shell. That's why, when we are calculating labor, material intensity and cost of these experimental researches. Keep in mind that this is promtly and relevant researches. In this work while planning the experiment some things were taken to consideration: best way for the construction to give the weight to reinforced concrete part and how to define the level of influence of factors like this: cyclicity, eccentricity, type of shell, thickness and diameter of shell, durability of concrete and deformation of reinforced concrete constructions.
 So, to get the most reliable information from these researches with minimal waste, we need to optimize parameter of load-bearing capacity and deformation and parameter of restriction-destruction. A calculation was made for optimizing the experiment about minimal amount of researches and conditions where they are done, and that is enough to salve the problem precisely.

Insights into sex-related size and shape dimorphism in Semisulcospira niponica (Caenogastropoda: Cerithioidea: Semisulcospiridae)

ABSTRACT Considerable intraspecific variation has been known in the shell morphology of the freshwater snail genus Semisulcospira. However, sexual dimorphism and allometric growth have not been elucidated in the genus, although these factors contribute to generating intraspecific variation. We used a combination of geometric and traditional morphometrics methods (GMM and TMM) in a single population of Semisulcospira niponica to assess sex-related differences in shell size and shape at maturity. The results of a generalized Procrustes analysis of variance revealed significant differences in shell size and shape between males and females. A principal component analysis (PCA) showed allometric differences between males and females; Principal component (PC) 1 values and their overlap between the sexes decreased with size. PC1 explained 35.5% of the total variance, which corresponded to vertical elongation of the shell spire and aperture, and broadening of the shell. The results of a canonical variate analysis using the ten largest specimens of each sex showed that females have less elongate shells with rounder apertures and a broader body and penultimate whorls than males. TMM using nine morphological characters supported shell morphological differences between the sexes and correlations between shell size and shape associated with different growth stages. However, GMM was more sensitive for detecting shape differences than TMM. For example, TMM explained the observed increase in shell diameter primarily as a function of size, whereas GMM detected sex-related differences in shell diameter as shape differences between the sexes. Furthermore, dimorphism and allometry in shell sculpture traits could be explored only by TMM. For accurate evaluation of shell morphology in Semisulcospira, it is important to use larger specimens after separating males and females since the present results revealed intersex differences in size and shape, some of which become more evident with age. It is also essential to employ both GMM and TMM because the two methods capture different aspects of morphological variation in shell outline and sculpture.

Bicomponent regenerated cellulose fibres: retaining the colour from waste cotton textiles

Bicomponent regenerated cellulose fibres (bRCF) have been created in a core–shell configuration from waste textiles. Textile dyeing and colouration is known to be a major contributor to the environmental impact of producing textiles and this needs to be addressed for textiles to become more sustainable. Coloration of the bRCF here was achieved by utilizing coloured textile waste in the shell component whilst using white cotton waste in the core. The shell and core extrusion speed and thus shell and core diameter were varied and optimised for colour strength. The optimised bRCF was made up of 49.6% dyed material yet was able to achieve the same colour strength as the single component regenerated cellulose fibre (RCF). The potential benefit of this approach is the reduced amount of coloured material required to colour these recycled fibres without any sacrifice in colour intensity. The mechanical properties of the bRCF were similar to the single component RCF with tensile strengths of 115–116 MPa and maximum elongations of 15.2–17.5%. The morphology of the bRCF was similar to single component regenerated cellulose fibres, while optical micrographs showed the discrete coloured core–shell structure of the bRCF. This manuscript details the fibre properties, dye savings and spinning approach.

A Numerical Simulation of Machining 6061 Syntactic Foams Reinforced with Hollow Al2O3 Shells

Aluminum closed cell syntactic foams possess reduced density, higher peak compression strength, and lower coefficient of thermal expansion and thermal conductivity compared to metal alloys. However, the industrial mass production of these complex material systems presents a significant problem in the form of poor machinability. In order to address this concern and to increase the use of this potential cost- and energy-saving system, a two-dimensional numerical model using the AdvantEdgeTM machining software was developed. For the verification of the numerical model, machining trials in dry conditions were conducted on different samples using a SandvikTM carbide-coated insert having a 6° rake angle and a 7° clearance angle. The hollow alumina shell diameter and volume fraction were found to profoundly affect the magnitude of the generated machining forces. This study showed an increase in machining force by almost 25% for syntactic foams reinforced with hollow alumina shells of higher volume fraction and coarser diameters. The cutting conditions to obtain a favorable stress diastribution in the syntactic foam’s machined sub-surface were identified.

Closed form solutions for thermo-mechanical buckling analysis of shallow piezo-laminated spherical shells

Thermo-mechanical buckling analysis of laminated spherical shells bounded with the piezoelectric actuator layers has been presented in this article. Applied loads are a combination of thermal, mechanical and electrical loads. Derivations of equilibrium and stability equations are based on the classical laminated shell theory and Sanders’s nonlinear kinematic relations. The analysis employs the Galerkin method to achieve closed-form formulas for the buckling loads of the piezo-laminated spherical shell. Effects of applied actuator voltage, voltage sign, geometrical parameters of the shell (length, diameter, and thickness), material properties, and layout of composite layers on the buckling strength are investigated. Analytical solutions are obtained for three types of thermal loading, and one thermo-mechanical loading condition. The results are validated by the known data in the literature.