Editor’s Note: The Year that Wasn’t

In February 2020, I was already planning the summer wall display in our children’s library room—I was planning on having a large pair of glasses with “20/20 Vision!” You know, perfect vision looking ahead to what a great year it would be!

Nematodes from the Tasmanian devil (Sarcophilus harrisii (Boitard)), with the description of Sarcophiloxyuris longus n. gen. and n. sp. (Oxyuridae)

The Tasmanian devil (Sarcophilus harrisii (Boitard)) is an endangered carnivorous marsupial, limited to the islands of Tasmania in southern Australia. The parasites of the Tasmanian devil are understudied. This study aimed to increase the knowledge of the nematode fauna of Tasmanian devils. Ten Tasmanian devils were examined for parasites from northern and southern Tasmania. Nematodes that were collected were morphologically characterized as two separate species. Molecular sequencing was undertaken to verify the identity of these species. A new genus and species of oxyurid nematode was collected from a single Tasmanian devil from the northern part of Tasmania. The nematode is differentiated from oxyurids described from other Australian amphibians, reptiles and marsupials by the characters of the male posterior end – that is, in having three pairs of caudal papillae, two pairs peri-cloacal, one large pair post-cloacal, a long tapering tail, a stout spicule and a gubernaculum and accessory piece, as well as its much larger overall size. Molecular sequencing was unsuccessful. The remaining nematodes collected from the Tasmanian devil in this study were all identified as Baylisascaris tasmaniensis Sprent, 1970, through morphology and molecular sequencing. This paper presents the first description of a new genus and species of oxyurid nematode from the Tasmanian devil, Sarcophiloxyuris longus n. gen., n. sp. The need to undertake more sampling of the parasites of endangered hosts, such as the Tasmanian devil, to assist with a better understanding of their conservation management, is discussed.

Schistonchus macrophylla (Nematoda: Aphelenchoididae): an enigmatic taxon from sycones of Ficus section Malvanthera in eastern Australia, with description of a new subspecies

Summary Over a period of 15 years, Schistonchus was collected from sycones of Ficus subgenus Urostigma section Malvanthera in eastern Australia, and was found to occur widely. Here, Schistonchus macrophylla macrophylla is redescribed from F. macrophylla and F. superba, and a new subspecies, Schistonchus m. lightfooti subsp. n., from F. rubiginosa and F. superba. Schistonchus m. lightfooti subsp. n., is characterised by having a long post-vulval uterine sac (PUS) with thickened walls and a narrowly rounded or pointed distal tip, procorpus which is usually longer than the stylet length, pyriform metacorpus, trapezoid-shaped head capsule, papillae arranged as one large pair adcloacal, a large pair at mid-tail length, and a small pair near the tail tip, no caudal alae, and a spatulate tail tip in females; and was collected from Sydney in New South Wales (NSW) to southern Queensland. Schistonchus m. macrophylla is characterised by having a procorpus shorter than or equal to the stylet length, an ovoid metacorpus, rectangular-shaped head capsule, long PUS with thickened wall only at its distal tip, caudal alae, and papillae arranged as one pair precloacal, one small pair adcloacal, and a large pair at mid-tail length. It was collected in NSW.

Morphological and molecular characterization of Travassosinema claudiae n. sp. (Oxyuridomorpha: Travassosinematidae) from the Japanese millipede Parafontaria laminata (Attems, 1909) (Polydesmida: Xystodesmidae)

Travassosinema claudiae n. sp. is described from the hindgut of the polydesmid millipede Parafontaria laminata (Attems, 1909) (Polydesmida: Xystodesmidae) from Aichi prefecture, Japan. Females of the new species resemble T. thyropygi Hunt, 1996 and T. travassosi Rao, 1958 by lacking lateral alae and the constriction of the body posterior to the level of the vulva. T. claudiae n. sp. differs from T. thyropygi by its shorter body and tail, and larger eggs. Also, the nerve ring is located in the procorpus-isthmus junction in opposition to T. thyropygi, where the nerve ring is just anterior to the basal bulb. T. claudiae n. sp. can be differentiated from T. travassosi by its shorter eggs and less extended cephalic umbraculum. Males of T. claudiae n. sp. are more similar to those of T. dalei Spiridonov & Cribb, 2012 by having a similar body length, form of the oesophagus, structures around the cloaca (mid-ventral, digitiform pre-cloacal pair of papillae, a large pair of adcloacal papillae and the anterior lip of cloaca ornamented and with a spatula-like post-cloacal projection), absence of spicule and gubernaculum, and presence of a tail filament. T. claudiae n. sp. differs by the position and type of ornamentation of the large ornamented pair of papillae, by lacking the minute pair of papillae in the tail filament and by the presence of lateral alae. Description is supplemented by SEM images. The phylogeny of the species is inferred by D2-D3 28S LSU rDNA and 18S SSU rDNA. This constitutes the first species of the genus Travassosinema Rao, 1958 described from Japan.

Calculating Energy Spectra from Drifters

The relations between the kinetic energy spectrum and the second order longitudinal structure function in two dimensions are derived, and several examples are considered. The forward conversion (from spectrum to structure function) is illustrated first with idealized power law spectra, representing turbulent inertial ranges. The forward conversion is also applied to the zonal kinetic energy spectrum of Nastrom and Gage (1985) and the result agrees well with the longitudinal structure function of Lindborg (1999). The inverse conversion (from structure function to spectrum) is tested with data from 2D turbulence simulations. When applied to the theoretical structure function (derived from the forward conversion of the spectrum), the result closely resembles the original spectrum, except at the largest wavenumbers. However the inverse conversion is much less successful when applied to the structure function obtained from pairs of particles in the flow. This is because the inverse conversion favors large pair separations, which are typically noisy with particle data. Fitting the structure function to a polynomial improves the result, but not sufficiently to distinguish the correct inertial range dependencies. Furthermore the inversion of non-local spectra is largely unsuccessful. Thus it appears that focusing on structure functions with Lagrangian data is preferable to estimating spectra.

A Numerical Study of Air-Side Heat Transfer Enhancement Using V-Formation Delta-Winglet Vortex Generators in Heat Exchangers

The numerical study proposed is to investigate the effectiveness of delta-winglet vortex generators (VGs) used for heat-transfer enhancement in a horizontal rectangular channel as a typical air passage for fin-and-tube heat exchangers. The effects of four different configurations of vortex generators have been investigated: (1) single pair VGs with a 30 degree attack angle; (2) 2-pair VG array with a 30 degree attack angle; (3) single pair VGs with a 45 attack angle; (4) 2-pair VG array with a 45 attack angle. The numerical results indicate that average Nusselt number increase is 31%–38% and 51%–71% for the channel mounted with VGs with a 30 degree attack angle and a 45 degree attack angle, respectively. The enhancement for single large pair of VGs is higher than that for a V-formation array with 2 small pairs. However, VGs also introduce extra pressure drop penalties to the channel flow, and higher heat-transfer performance is also accompanied by a larger pressure drop penalty. According to the results, a single large pair of VGs with 45 attack angle shows the best overall performance among all the configurations investigated.

Study on the Influence of the Damping to Nonlinear Vibration Caused by Pair Clearance

Because the two components have relative motion, pair clearance is inevitable. With the machine’s speed increasing, nonlinear vibration phenomenon caused by clearance is much obviously. The state of damping in pair clearance will often make mechanism’s nonlinear vibration appear different status. For the study of damping in joint clearances impact to nonlinear vibration, four-bar mechanism with clearance is taken as research object. A nonlinear dynamic model has been established based on continuous contact model. Through analysis the nonlinear vibration in different damping and clearance, it can be found that in weak damping condition, nonlinear vibration in small pair clearance is more sensitive to the small changes of damping than that in large pair clearance. So, it’s very important to keep the pair clearance in proper lubrication conditions.

Air-Side Heat-Transfer Enhancement by a New Winglet-Type Vortex Generator Array in a Plain-Fin Round-Tube Heat Exchanger

The impact of a vortex-generation technique for air-side heat-transfer improvement is experimentally investigated through full-scale wind-tunnel testing of a plain-fin round-tube heat exchanger under dry-surface conditions. Inspired by the formation locomotion of animals in nature, a new vortex generator (VG) array deployed in a “V” is proposed in the present work, aiming to create constructive interference between vortices. The array is composed of two delta-winglet pairs and placed at an attack angle of 10 deg or 30 deg. Its effectiveness is compared with a baseline configuration and two conventional single-pair designs placed at 30 deg, a small pair with half the area of the array and a large pair with the same area as the array. The frontal air velocity considered ranges from 2.3 m/s to 5.5 m/s, corresponding to a Reynolds number range based on the hydraulic diameter of 1400–3400. The experimental results show little impact of the 10 deg array and a moderate heat-transfer improvement of up to 32% for the small pair, both introducing additional pressure loss of approximately 20–40%. For the 30 deg array and the large pair, similar augmentation of 25–55% in air-side heat-transfer coefficient is obtained accompanied by average pressure drop penalties of 90% and 140%, respectively. Performance evaluation using the criteria of the modified area goodness factor and the volume goodness factor indicates the superiority of the heat exchanger enhanced by the 30 deg array among all the investigated VGs. The VG array is found more effective at comparatively low Reynolds numbers, representative of many heating, ventilation, air-conditioning, and refrigeration applications and compact heat-exchanger designs.