Tube Elements Research Articles

Simulation and Experimental Studies of a Multi-Tubular Floating Sea Wave Damper

This article explores the issue of shore protection from sea waves and has presented the main methods used for coastal protection. It discusses the construction and operation of the multi-tubular floating sea wave damper that has been developed at the Maritime University of Szczecin by Professor Bolesław Kuźniewski. This paper presents the results of the research project aimed at creating and examining a prototype of the device. The research aimed to confirm the two hypotheses: “the largest damping force should occur when the damping units are placed at an optimal distance equal to half the length of the wave to be damped” and “a compensation of the horizontal forces caused by the rippling of water should occur in the damping device”. Simulation studies of the behaviour of the device’s buoyancy elements when floating on waves were performed using the ANSYS AQWAWB and AQWA software. The buoyancy components were modelled as TUBE elements with a diameter of 0.11 m and a length of 1.5 m and as triangular and square surface elements. The results of the experimental research and the computer simulation of the operation of the prototype device have also been presented. The external conditions adopted corresponded to the frequency of a wave equal to 0.807 Hz and to the wave height in front of the device which was equal to 0.1 m. Experimental studies were conducted in an auxiliary model basin with dimensions of 60 m × 7 m × 3.12 m at the Ship Hydromechanics Division, Ship Design and Research Centre (CTO S. A.) in Gdańsk (Poland). The study recorded the distribution of the vertical and horizontal forces acting on the prototype device as well as the wave height both in front of and behind the device. Both hypotheses were proven. Simulation and experimental studies have been summarised. A proposal for future works has also been presented.

Morphology, structure and ultrastructure of staminal nectary in Lamprocapnos (Fumarioideae, Papaveraceae)

Nectaries show high a degree of variations in terms of location, morphology and structure; these characteristics are critical for systematic information. In Papaveraceae, staminal nectaries at the stamen base are only found in bisymmetric and zygomorphic flowers, but with little description on the ultra-structure of nectary available. Here we investigate structural details of flowers and nectaries of Lamprocapnos spectabilis using LM, SEM and TEM. The nectaries of L. spectabilis are initiated at the base of stamen filaments in the young bud. The oval/ball-shaped staminal nectaries are composed of four major types of tissues in general. First and outmost layers are epidermis and hypodermis with large and elliptical cells. Beneath the epidermal layers are the second type of tissue consisting of 20–30 layers of parenchyma cells which are further distinguished by two kinds of cells: smaller secretory parenchyma cells having dense cytoplasm, large nucleus and abundant cellular organelles, and larger sub-nectary parenchyma cells containing a relatively thin cytoplasm. The third type of tissue is the darkly-stained elongated cells and embedded at 8- to 12-cell-layer deep in the nectaries, and is associated with sieve tube elements and cells resembling companion cells, and they presumably belong to underdeveloped sieve tube elements or “protophloem” based on ultrastructure features such as conspicuous cell wall ingrowths and plentiful plasmodesmata. The forth type of tissue in the nectary is the simplified vascular bundle forming with only phloem. It is reasonable to suggest that secretions in the spacious intercellular spaces between secretory parenchyma cells are exuded to the exterior via micro-channel or epidermis/cuticle pathway. In conclusion, the results show that epidermis, hypodermis, secretory parenchyma, “Arber suggestive tissue (protophloem)”, and phloem act coordinately in nectar production, secretion and exudation in Lamprocapnos. The structure of the staminal nectaries are compared within Papaveraceae and with other related groups in Ranunculales.

On Deformation Charting for Concrete Filled Steel Tube Columns Concrete Core and Steel Shell

New approach to creating deformation charts for concrete core and steel shell of round CFST columns is offered. For creating such charts the power resistance of short central the compressed concrete filled steel tube element is considered. At the same time two major factors are considered. First, the steel shell and the concrete core function under conditions of complex tension. Secondly, at step-by-step strengthening of axial deformations the side pressure upon concrete core and steel shell constantly changes. As a result coordinates of parametrical points of deformation charts for concrete and steel change. Such approach allows describing the real intense deformed condition of concrete filled steel tube columns more precisely.

Failure Study of Compression Glass-Metal Joint for Parabolic Trough Receiver Tube application

The concentrated solar power plant technology has been proven to be a latest source for generation of renewable energy. Its performance depends on efficiency of the parabolic trough receiver tube or heat collecting element (HTC). In this paper, experimental study on fabrication of glass metal joint has been elaborated for parabolic trough receiver tube. Borosilicate glass tube was joined with austenitic stainless steel (SS304) metal ring using compression glass-metal type assembly with the help of induction heating and using 40SiO2-54B2O3-4Na2O-2Al2O3 material as the glass sealant. The process parameters for joining were selected on the basis of wettablity, pre-oxidation and microstructure studies. The generated residual stresses in glass tube after fabrication process was measured experimentally with the help of photo elastic technique using polariscope ‘PS-100-BS’. From the experimental results, it was observed that, the intensity of residual tensile stress in glass tube increases as thickness of metal ring increases. The cracking of glass just 1mm above the interface was also observed corresponding to maximum metal thickness ring.

Experimental Performance Studies of Improving Compressed Concrete Filled Steel Tube Elements of Square Section

Abstract The objective of the present work is improving compressed concrete filled steel tube elements of square section by means of helical reinforcement of a concrete core. Conducted experimental studies of centrically and eccentrically compressed laboratory samples of such elements have shown that in comparison with similar samples without helical reinforcement their durability ha increased by 31÷42%. Values of longitudinal sample deformation fixed at maximum with helical reinforcement made of C25 concrete class have increased almost 3 times. Maximum longitudinal sample deformation made of C50 concrete class were inferior by 20%. Increase in durability and deformability of improved samples is explained by increase in performance of placing of shear reinforcement that is ensured by helical reinforcement. Confining element ration at central compression was equal to 1.36÷1.9, at eccentrical compression with eccentricity ratio of 0.107 it was 1.28÷1.35, and at eccentricity ratio of 0.214 -1.15÷1.26. High durability and deformability ensure greater tenacity of such structure that makes them attractive for usage in buildings and constructions in areas with increased seismic activity. The revealed features of strength resistance of concrete filled steel tube elements with square section will be used when developing an algorithm and a computer program for the automated calculation of their bearing capacity.

Heterogeneous distribution of pectin and hemicellulose epitopes in the phloem of four hardwood species

Key messageDistributional patterns of pectin and hemicellulose epitopes in the phloem of four hardwoods vary between cell types including sieve tube elements, companion cells, parenchyma and sclerenchyma and between tree species.Using immunolocalization methods combined with monoclonal antibodies, the distribution of pectin and hemicellulose epitopes was examined in the secondary phloem of two diffuse porous (birch, aspen)- and two ring porous (oak, ash) hardwoods with a focus on sieve tube elements (SEs), companion cells (CCs), axial/ray parenchyma cells, and sclerenchyma cells (sclereids and phloem fibers). In all tree species, rhamnogalacturonan-I (RG-I), homogalacturonan (HG), and xyloglucan epitopes were common in cell walls of SEs, CCs, and axial/ray parenchyma cells. However, the amount of these epitopes varied greatly between cell types and between hardwood species. Apart from aspen, heteroxylan or/and heteromannan epitopes were detected in SEs, but were not detected in CCs and parenchyma cells. With sclerenchyma cells, RG-I, HG, and xyloglucan epitopes were common in compound middle lamellae (CML) of sclereids and phloem fibers. Except for oak, heteromannan epitopes were also detected in CML of sclereids. Distributional patterns of epitopes in CML of birch and ash sclereids varied greatly depending on anatomical structure of CML. Secondary cell walls of sclereids and phloem fibers revealed abundant heteroxylan epitopes, but showed no heteromannan epitopes. Some phloem fibers also showed sparse xyloglucan epitopes in secondary cell walls. Together, results suggest that there are great variations in distributional patterns of pectin and hemicellulose epitopes in hardwood phloem between cell types and between tree species.

Bending moment and axial compression interaction of high capacity hybrid fabricated members

Along with proposing any innovative structural element for design purposes it is necessary to understand its behaviour under combined structural actions. This paper includes experimental, numerical and analytical investigations on an innovative type of hybrid fabricated section consisting of high strength tubes and mild steel plates under the effect of axial compression and bending moment interaction. As a special case of interactive condition, pure bending performance of the hybrid fabricated member is examined with focus on the local failure mechanisms and analytical expressions are proposed to predict the moment resisting capacities. Furthermore, compression-bending interaction curves are obtained from plastic analysis of hybrid hollow sections and compared to relevant standard formulations. The compression-bending curves obtained for various ratios of tube cross-section and strength to that of plate show that a linear interaction formula is applicable to predicting the plastic interaction behaviour of sections with high ratios while sections with lower ratios are closely predicted by a bilinear interaction formula. This paper also includes beam-column tests accommodating combined effects of compression, bending and also shear. Employing the developed and validated finite element model, a parametric study is conducted on the effect of section geometry and material on the axial-lateral interaction of beam-columns. Referring to the member interaction results, reaching an optimum interactive performance stands on the design of both geometry and material of plate and tube elements.

Springback predictions for three-dimensional thick-walled tubes based on the cylindrical helix splines

This article analyzed the forming process of thick-walled three-dimensional tubes under combined bending and twisting loads and performed the springback predictions based on the cylindrical helix splines. The equations to calculate the two kinds of moments consider the hardening effect, and they can be well applied to most materials. The cylindrical helix spline is adopted creatively to approximate the objective tube axis, and the curvature and the torsion of each cylindrical helix segment can represent the bending angle and the twisting angle per unit length of the corresponding tube element, respectively. All the cylindrical helix segments after springback are obtained based on the calculated moments and the final shape of the tube axis is achieved by connecting all of them through an appropriate splicing technology. Then, the whole deviations of the calculated shapes can be obtained. The method proposed is applied on a typical three-dimensional tube forming and it has got good effect.

Intermediate‐Valence Intermetallic Phase YbIn1–xAu1+x (x = 0‐0.3)†

AbstractPolycrystalline samples YbIn1–xAu1+x were prepared by reaction of the elements in sealed tantalum tubes at 1170 K with a subsequent annealing at 770 K. The crystal structures of YbInAu (space group P6;−2m, a = 7.6992(8), c = 4.0333(5) Å, wR2 = 0.035, 282 reflections and 14 variables) and YbIn0.73Au1.27 (P6;−2m, a = 7.706(3), c = 4.011(1) pm, wR2 = 0.035, 275 reflections, 14 parameters) were refined from single crystal X‐ray diffraction data. The phase YbIn1–xAu1+x has a homogeneity range for 0.0≤x≤0.3 (770 K). The crystal structure of YbInAu contains two gold atoms located in tricapped trigonal prisms [Au1Yb6In3] and [Au2In6Yb3]. The indium position shows mixed occupancy by indium and gold. The main atomic interaction is the ionic one between the ytterbium (charge +1.1 is obtained from the analysis of the electron density within the quantum theory of atoms in molecules) and gold (−1.2 and −1.3) supported by the dative bonding Au→Yb. The effective charge of indium is +0.2. Magnetic susceptibility data indicate intermediate valence for Yb increasing with increasing x. The 197Au Mössbauer spectra show a superposition of the signals for Au1 (δ = 3.31 mm s–1), Au2 (δ = 5.37 mm s–1), and Au(In) indicating auridic character of gold.

Simulation and Optimization of Throttle Flowmeter with Inner-Outer Tube Element

Abstract In order to solve the dilemma between the smaller pressure loss and the larger flow measurement signal in traditional throttle flowmeters, a throttle structure with the inner-outer tube was designed and analyzed. The mathematical relationship model deduced from hydrodynamics showed there were three major parameters to determine the designed throttle structure. Furthermore, the optimal results were achieved by combining orthogonal test design and computational fluid dynamics by taking the ratio of differential pressure of inner-outer tube divided by that of anterior-posterior tube as the optimization goal. Finally, the simulation results with the best level parameters showed that the differential pressure of the anterior-posterior throttle could remain not only the smaller value among other parameters with the same structure of inner-outer tube. On the other hand, it was about one order magnitude less than differential pressure of V-cone flowmeter in the similar installation conditions with the flow velocity varying from 0.5 to 3.0 m/s. The designed inner-outer tube flowmeter can not only save manufacture costs, but also avoid the large sensitivity of pressure sensors, which may lead to a broader application in chemical and petrochemical enterprises.

Death of pastures syndrome: tissue changes in Urochloa hybrida cv. Mulato II and Urochloa brizantha cv. Marandu.

The quality of forage production is a prerequisite to raising livestock. Therefore, income losses in this activity, primarily cattle raising, can result in the impossibility of economic activity. Through the qualitative and quantitative anatomical study of Urochloa hybrida cv. Mulato II and U. brizantha cv. Marandu, we searched for descriptions and compared changes in the individual vegetative body from populations with death syndrome pastures (DPS). Specimens were collected at different physiological stages from farms in northern Mato Grosso. After collection, the individuals were fixed in FAA50 and stored in 70% alcohol. Histological slides were prepared from the middle third of the sections of roots, rhizomes, and leaves, and the proportions and characteristics of tissues were evaluated in healthy, intermediate, and advanced stages of DPS. Changes were compared between cultivars. With the advancement of the syndrome, the following changes were observed: a more marked decrease in the length of roots in U. hybrida; disorganization of the cortical region of the roots and rhizome cultivars; fungal hyphae in roots and aerenchyma formation in U. hybrida; a decrease in sclerenchyma fiber proportions in roots and leaves; sclerification of the epidermis of U. brizantha rhizomes; and an increase in pericyclic fibers in U. hybrida. Furthermore, there was a decrease in the volume of epidermal cells of the abaxial face of the leaves of both cultivars, with a greater reduction in U. hybrida; a gradual decrease in thickness in the midrib of leaves similar to leaf mesophyll; conduction system obstructions; partial or total cell lysis in roots and rhizomes affected by the syndrome. Obstructions in sieve tube element and companion cells, and sometimes obstruction in xylem vessel elements. The evolution of DPS in cultivars was similar, but there were variations, arising probably from the physiological response to stress, such as aerenchyma formation in the root and increased pericycle in the rhizome of U. hybrida.

Local infection associated with vascular bundles: the colonization of coconut palm leaflets by two Camarotella species

Two Camarotella (Phyllachoraceae) species, C. torrendiella and C. acrocomiae are the causative agents of small (SV) and large verrucosis (LV), respectively, which are important diseases affecting Brazilian coconut palms. The small verrucosis produces necrotic lesions in coconut palm leaflets, whereas LV just produces chlorosis. Semi-thin sections of asymptomatic leaflets and of leaves presenting stromata in different development stages were compared through light microscopy in order to characterize the colonization process of these two coconut palm verrucosis agents. Camarotella torrendiella initially colonized the adaxial epidermal cells and the cells underlying the epidermis close to the vascular bundles. In latter colonization stages, the hyphae of C. torrendiella remained limited to the underlying necrotic tissue adjacent to the mature stromata, mostly in the intracellular spaces and in the collapsing cells of necrotized tissues around the vascular bundles. This species does not colonize intracellular intact fiber cells, xylem vessels or phloem sieve tube elements. In contrast, C. acrocomiae presented a typical biotrophic parasitism model such as that of some gramineous Phyllachora spp. High densities of C. acrocomiae hyphae were found inside intact sieve tube elements; however, with no evidence of cellular death. The extensive hyphal colonization by C. acrocomiae within sieve tube elements was also observed in tertiary and quaternary bundles, as well as in anastomosing vascular bundles. The dependence of both species on the colonization sites associated with vascular bundles indicates the need for additional studies about these intricate host-pathogen relationships. These studies could be important to define new strategies to control coconut palm verrucosis diseases.

Internal cambium and intraxylary phloem development in Ipomoea turbinata Lag. (Convolvulaceae)

Strands of phloem that are present at the periphery of pith are known as intraxylary phloem. Its presence remains restricted to a small portion of eudicots and considered as a characteristic feature for certain families. In the present study, Ipomoea turbinata Lag. showed development of intraxylary protophloem on adaxial tips of protoxylem from the procambial derivatives. Subsequently, additional intraxylary sieve elements were added from the adjacent parenchyma cells that were morphologically different from the pith cells. In thick stems, thin walled cells located between protoxylem and intraxylary protophloem acquired meristematic characters and formed several small segments of internal cambium. Initially, these cambial segments produced only phloem derivatives. Soon after, these segments became bidirectional and began to produce secondary xylem centrifugally and secondary phloem centripetally. Interestingly, in some of the samples development of secondary phloem and xylem was observed in the same direction. The secondary xylem formed by the internal cambium was composed of wide and fibriform vessels, fibres and axial parenchyma. Phloem possessed sieve tube elements, companion cells and parenchyma cells while rays in both xylem and phloem were mostly uniseriate but multiseriate rays were also observed.

Temperature affects the morphology and calcification of <i>Emiliania huxleyi</i> strains

Abstract. The global warming debate has sparked an unprecedented interest in temperature effects on coccolithophores. The calcification response to temperature changes reported in the literature, however, is ambiguous. The two main sources of this ambiguity are putatively differences in experimental setup and strain specificity. In this study we therefore compare three strains isolated in the North Pacific under identical experimental conditions. Three strains of Emiliania huxleyi type A were grown under non-limiting nutrient and light conditions, at 10, 15, 20 and 25 °C. All three strains displayed similar growth rate versus temperature relationships, with an optimum at 20–25 °C. Elemental production (particulate inorganic carbon (PIC), particulate organic carbon (POC), total particulate nitrogen (TPN)), coccolith mass, coccolith size, and width of the tube element cycle were positively correlated with temperature over the sub-optimum to optimum temperature range. The correlation between PIC production and coccolith mass/size supports the notion that coccolith mass can be used as a proxy for PIC production in sediment samples. Increasing PIC production was significantly positively correlated with the percentage of incomplete coccoliths in one strain only. Generally, coccoliths were heavier when PIC production was higher. This shows that incompleteness of coccoliths is not due to time shortage at high PIC production. Sub-optimal growth temperatures lead to an increase in the percentage of malformed coccoliths in a strain-specific fashion. Since in total only six strains have been tested thus far, it is presently difficult to say whether sub-optimal temperature is an important factor causing malformations in the field. The most important parameter in biogeochemical terms, the PIC : POC ratio, shows a minimum at optimum growth temperature in all investigated strains. This clarifies the ambiguous picture featuring in the literature, i.e. discrepancies between PIC : POC–temperature relationships reported in different studies using different strains and different experimental setups. In summary, global warming might cause a decline in coccolithophore's PIC contribution to the rain ratio, as well as improved fitness in some genotypes due to fewer coccolith malformations.

Oil Secretory System in Vegetative Organs of Three Arnica Taxa: Essential Oil Synthesis, Distribution and Accumulation.

Arnica, a genus including the medicinal species A. montana, in its Arbo variety, and A. chamissonis, is among the plants richest in essential oils used as pharmaceutical materials. Despite its extensive use, the role of anatomy and histochemistry in the internal secretory system producing the essential oil is poorly understood. Anatomical sections allowed differentiation between two forms of secretory structures which differ according to their distribution in plants. The first axial type is connected to the vascular system of all vegetative organs and forms canals lined with epithelial cells. The second cortical type is represented by elongated intercellular spaces filled with oil formed only between the cortex cells of roots and rhizomes at maturity, with canals lacking an epithelial layer.Only in A. montana rhizomes do secretory structures form huge characteristic reservoirs. Computed tomography illustrates their spatial distribution and fusiform shape. The axial type of root secretory canals is formed at the interface between the endodermis and cortex parenchyma, while, in the stem, they are located in direct contact with veinal parenchyma. The peripheral phloem parenchyma cells are arranged in strands around sieve tube elements which possess a unique ability to accumulate large amounts of oil bodies. The cells of phloem parenchyma give rise to the aforementioned secretory structures while the lipid components (triacylglycerols) stored there support the biosynthesis of essential oils by later becoming a medium in which these oils are dissolved. The results indicate the integrity of axial secretory structures forming a continuous system in vegetative plant organs.

RE 3Au5Zn (RE = Y, Sm, Gd–Ho) – A new structure type with five- and six-membered rings as building units in a gold network

Abstract RE 3Au5Zn (RE = Y, Sm, Gd–Ho) intermetallic compounds were synthesized by melting the elements in sealed tantalum tubes. They exhibit a new structure type which was studied by X-ray diffraction on powders and refined from single crystal diffraction data: Cmcm, a = 736.9(2), b = 1489.4(2), c = 1330.4(3) pm, wR2 = 0.0371, 1184 F 2 values and 55 variables for Y3Au4.92Zn1.08 and a = 739.0(1), b = 1495.8(2), c = 1339.2(2) pm, wR2 = 0.0325, 1410 F 2 values and 54 variables for Tb3Au5Zn. The network consists of five- and six-membered gold rings in puckered conformations. Atoms of the rare earth elements are placed within the cavities of this network where every third cavity is filled by a Zn2 dumbbell. The structure is discussed in detail and compared with the gold substructure of Hf7Au10.

Application of high strength and ultra-high strength steel tubes in long hybrid compressive members: Experimental and numerical investigation

With the increasing application of high strength steel material in industries, there is a high potentiality for taking advantage of the exceptional load-bearing capacities of this material in construction practice. In the present study, an innovative application for high and ultra-high strength steel material is proposed which enhances the overall behavior of structural elements. The high strength and ultra-high strength steel with nominal tensile strengths of 750MPa and 1250MPa, respectively, are proposed to be utilized as tube elements welded to corners of mild steel plates shaping an innovative hybrid section. This section takes advantage of the combined material properties of the two constituting elements in terms of strength, local buckling behavior and ductility. Large-scale tests and numerical analysis have been conducted to compare the behavior of the proposed sections against conventional welded sections. The effect of heat on the material properties of the hybrid section has also been considered. These effects are included in the finite element modeling of innovative columns where numerical outputs have been verified accordingly.

Application of light microscopic staining techniques for the detection of phytoplasmas in yellow leaf disease affected arecanut palms in India

Yellow Leaf Disease (YLD) is one of the most drastic diseases affecting the areca nut palms of Kerala and Karnataka causing extensive crop loss. The disease is associated with phytoplasma presence. A classic diagnostic technique was the observation of symptoms on the leaves however microscopic studies can be used for pathogen visualization along with molecular methods. Although the direct observation of phytoplasmas requires the magnification achieved only by electron microscopy, light and fluorescence microscopy can also be used to detect the presence of phytoplasmas in diseased palm tisues. Dienes’ stain and DAPI fluorescent microscopic method developed for confirming the presence of phytoplasma in hand cut or freezing microtome sections of infected tissues were employed. In the present study, YLD affected plants gave positive results for phytoplasma specific staining. Fluorescent particles of the DAPI-stained phytoplasma were limited to sieve tube elements. Phloem of healthy root sections remained unstained with Dienes’ stain, but phloem of the infected root sections contained many dark blue DAPI stained areas. The results from the present study indicated that these methods can be used as preliminary steps in phytoplasma presence detection, and are found to be very effective in highly infected plants. The microscopic observation of phytoplasma cells could be used as a confirmative step for subsequent application of molecular diagnostic techniques.

Magnetic properties of RE 10 TCd3 (RE = Ho, Er, Tm, Lu; T = Fe, Co, Ni, Ru) and 57Fe Mössbauer spectroscopic data of Y10FeCd3

Abstract Fourteen X-ray-pure intermetallic compounds RE 10 TCd3 (RE = Ho, Er, Tm, Lu; T = Fe, Co, Ni, Ru) and Y10FeCd3 were obtained through high-frequency melting of the elements in sealed niobium tubes and subsequent annealing in a muffle furnace. They adopt the Er10FeCd3 structure, a ternary ordered version of the Co2Al5 type. Temperature-dependent magnetic susceptibility measurements show Pauli paramagnetism for the lutetium compounds Lu10FeCd3, Lu10CoCd3, and Lu10RuCd3. The RE 10 TCd3 phases with holmium, erbium, and thulium show Curie–Weiss paramagnetism and the experimental magnetic moments match with the free ion values of RE 3+. All these compounds order antiferromagnetically. The highest Néel temperature was observed for the holmium compounds, e.g. 46.5 K for Ho10RuCd3. Some of the RE 10 TCd3 phases show field-induced spin reorientations. A 57Fe Mössbauer spectrum of Y10FeCd3 confirms the single crystallographic iron site.

The Endoscopic Endonasal Approach to the Hypoglossal Canal: The Role of the Eustachian Tube as a Landmark for Dissection.

Improvements in endoscopic technology and reconstructive techniques have made the endoscopic endonasal approach (EEA) a viable option to approach ventromedial lesions in the region of the hypoglossal canal. Prior to contemplating this surgical corridor, a thorough understanding of anatomic relationships and landmarks is essential to safely approach this region of the posterior skull base through an EEA. To describe the surgical technique and anatomic landmarks in the EEA to the hypoglossal canal through referencing nasopharyngeal and posterior skull base anatomy. Study of latex-injected cadaveric heads at the North Carolina Eye Bank Multidisciplinary Surgical Skills Laboratory at the University of North Carolina. An EEA to the hypoglossal canal was carried out bilaterally in 5 embalmed, latex-injected cadaver heads. Cadaveric measurements of anatomic landmarks and relationships in the approach were obtained using a 10-cm surgical ruler and were reported as mean distances. Additionally, high-quality endoscopic images demonstrating the operative technique and anatomic relationships were obtained. The distance between the lacerum segment of the internal carotid arteries, the superolateral boundary, was 23.6 mm (SD, 11.8 mm). The distance between the anterolateral edge of the occipital condyles, the inferolateral boundary, was 19 mm (SD, 0.80 mm). The supracondylar groove was identified in the same anteroposterior plane as the nasopharyngeal orifice of the eustachian tube, and the anterior-most edge of the occipital condyle was 14 mm (SD, 0.82 mm) from the posterosuperior edge of the salpingopharyngeal fold. Additionally, the transtubercular corridor was on the same plane as the superior edge of the torus tubarius in the anteroposterior axis. The distance to the hypoglossal canal from midline was 10 mm, which was found after completing drilling in the transcondylar and transtubercular corridors. Last, the hypoglossal nerve rootlets were identified entering the canal 6 mm inferiorly and 8 mm laterally from the vertebrobasilar junction. The eustachian tube and other elements of nasopharyngeal anatomy are fixed landmarks that provide important points of reference when approaching the hypoglossal canal through an EEA. A thorough understanding of these anatomic relationships is vital in safely navigating this direct, surgical corridor to the posterior fossa.