Journal articles on the topic 'Guide d'onde à section variable'

The problem of variable cross-section beam carrying a moving heavy load is investigated. UG software is used to build a three-dimensional model of the beam. The finite difference method and finite element method are used static analysis for the variable cross-section beam carrying a moving heavy load. The static deformation of the beam guide surface is obtained. Comparing the data of the two method, the feasibility of the method is verified. This paper give a guide surface load curve research method of variable cross-section beam carrying a moving heavy load.

There is so much influence to the fatigue life of the whole structural component from cross-section transition zone radian, and more than 100 times difference is made by different structural details for fatigue life [1]. According to structure and features of variable cross-section strut-and-tie,combing with its’ geometric properties and applied stress ways, at the basis of nominal stress method, the fatigue life of variable cross-section strut-and-tie is analyzed in the paper. Then, transitional zone is improved and fatigue life is analyzed. At last, the improved is compared with previous structure and analysis of Influence of fatigue life from variable cross-section strut-and-tie transition zone radian in theoretical. The conclusions of this paper guide other similar researches.

Trip steel is broadly used in automobile manufacturing with its high strength and enhanced formability. For the variable section parts with protrusion and hole, roll forming is a kind of feasible way to realize continuous parts manufacturing, In the paper, with deep understanding of roll forming process and reasonable simplification, the FEM model of a multi-step variable section roll forming of 600MPa trip steel parts with protrusion and hole is established to analyze the mechanics and the deformation characteristics of the forming procedure. Equivalent stress, equivalent strain, sheet thickness and springback amount are extracted from the simulation result and studied comparatively, which is of great importance to understand the appearance of the forming defects. In addition, the forming load and torque of the rollers can also be obtained to guide the design of the variable section roll forming product line.

The construction with hanging basket eccentric loading was studied for the cantilever casting of a 32m +48 m +32 m continuous box girder. The calculation of center deflecting angles of cantilever box girders with variable cross-section due to pure torsion was derived, and correspondingly a program was developed to calculate this formula. An analysis model of cantilever casting continuous beam bridge with hanging basket eccentric loading was established based on finite elements software, and the shear stress, the longitudinal normal stress and the combined stress of different section were analyzed under different construction process. The torsional effect due to hanging basket eccentric loading was studied and the results are helpful to guide the construction in practice.

As the sensor probe occupies a small proportion of the cross-sectional area of the pipe, the concentration of nitrogen oxides measured by the sensor may not reflect the average concentration of nitrogen oxides at the measured section when the uniformity of the nitrogen oxides is poor. The uniformity of the nitrogen oxides at the measured section is influenced by the structure of the selective catalytic reduction system of the vehicle, and particularly by the structure of the variable cross-section behind the catalyst. In this paper, a model of the selective catalytic reduction system is established to explore the rules for influencing the uniformity of the nitrogen oxides. The conclusion shows that the uniformity of the nitrogen oxides is influenced by five structure factors, which are as follows: the nozzle location; the structure of the mixing chamber; the exhaust velocity; the pipe-diameter ratio of the variable-cross-section structure; the distance between the measured section and the catalyst and the catalyst outlet. When the nozzle is further away from the catalyst inlet and the mixing chamber is designed as a cone-shaped guide plate, the uniformity of the nitrogen oxides is better. When the relative flow velocity is greater than 4.5–7.5 s−1, the uniformity of the nitrogen oxides is positively related to this factor; otherwise, the uniformity stays invariant. When the pipe-diameter ratio of the variable cross-section is 0.34, the uniformity of the nitrogen oxides is the best. The distance between the measured section and the catalyst outlet is logarithmically related to the uniformity of the nitrogen oxides. Based on the laws for the parameters influencing the uniformity of the nitrogen oxides, the structure of selective catalytic reduction in a vehicle can be optimized to improve the objectivity of the measurements, thereby guaranteeing the accuracy of the vehicle’s on-board diagnostic system, in which the nitrogen oxides sensor is applied.

The top drive for casing running system can effectively avoid borehole neck down and sticking, reducing construction period by about 50%. However, the casing will bear higher torque load, and the casing joint threads can meet the bearing performance, which have a critical impact on casing running and the life of oil and gas wells. Variable pitch can reduce thread stress concentration and improve load-bearing strength. Lacking research on mechanical behavior has greatly restricted the development of variable pitch thread. This article generated a variable pitch casing joint thread helix forming method and control equation; designed an ultrahigh-torque variable pitch casing joint thread based on the theory of screw transformation matrix; established a three-dimensional finite element model of the variable pitch casing joint; optimized the main structure parameters with the judgment of torque-bearing capacity; and conducted parameter-sensitivity evaluation of guide surface angle, bearing surface angle, pitch of box thread, and amount of varying pitch under tension load, compression load, bending load, and torque load. The designed variable pitch casing joint had been successfully used in several top driving casing running wells, downed to the maximum depth of 4375 m, the largest hole deviation angle of 55.37° and horizontal section length of about 260 m. Under a torque of 4000 N m, the top drive rotated down into the gas well successfully without failure. The research work of this article has significance on variable pitch thread and enhances the bearing capacity of the thread.

Background The reliability of intraoperative evaluation of ganglion cells in the appendix as a guide to a diagnosis of total colonic aganglionosis is unclear. Objective To evaluate the diagnostic utility of appendicular innervation in colonic Hirschsprung disease (HD) and TCA. Methods Prospective, systematic study of ganglion cells and the neural plexii in appendices from cases (HD and TCA) and age matched controls with frozen and paraffin sections, rapid acetylcholinesterase (AChE) and immunohistochemistry. Results A total of 48 appendices (28 controls, 20 cases; 19 frozen) were evaluated. Of these 48, 30 were neonates. Ganglion cell clusters were smaller in controls (28) and HD (6) than those in the rectum, distorted at places and mimicked lymphocytes and endothelial cells, especially in neonates. Complete study of 13 appendices in TCA showed absence of ganglion cells, hypertrophic nerves, AChE activity, and calretinin staining. In 2/13 TCA, an erroneous frozen section identification of ganglia was later corrected based on AChE histochemistry and a panel of IHC stains. Ileal biopsies guided the placement of a ganglionic ileostomy in all. One case each of skip segment aganglionosis in a TCA and variable hypoganglionosis in long segment colonic HD is reported. Conclusion Intraoperative characterization of appendicular innervation as a guide to the diagnosis of TCA is unreliable, in part because of the possibility of skip segment disease/variable hypoganglionosis. We propose terminal ileal biopsies for diagnosis and leveling of aganglionosis. AChE on frozen/calretinin on paraffin tissue is the best approach to avoid diagnostic errors.

In this paper, a novel restrainer called steel ring restrainer (SRR) is proposed to prevent the unseating of bridges. The restrainer is comprised of a steel ring, an upper guiding pulley, a downward guiding pulley, and two connections. The SRR can provide different stiffnesses under different seismic excitations. The SRR is not activated under daily load but provides smaller stiffness in small and medium earthquakes and even larger stiffness in strong earthquakes. The stiffness changes smoothly from small and medium earthquakes to strong earthquakes. This mechanism called buffer capacity reduces the impact on the connection between the SRR and structure. In order to study the effect of each design parameter on the mechanical properties of the SRR, 54 finite element (FE) models in four groups were established and analyzed. The results show that the diameter of the cross-section of the steel ring has an important influence on the initial stiffness, secondary stiffness, buffering capacity, and ultimate bearing capacity of the SRR, the radius of the curved part of the steel ring significantly affected the initial stiffness and ultimate displacement, the nonworking length of the SRR was decided by the length of the straight part of the steel ring, and the diameter of the guide pulley governed the ultimate bearing capacity and ultimate displacement. Additionally, the predicted formulas of the design parameters were derived and eight models were employed to investigate the effectiveness of the formulas, in order to be applied in the seismic design.

Parametric optimization problem for single edge fold size in cold-formed structural members subjected to central compression has been considered by the paper. Determination the load-bearing capacity of the cold-formed structural members has been performed using the geometrical properties calculated based on the constructed “effective” (reduced) cross-sections taking into account local buckling effects in the section as well as distortional buckling effects. Single edge fold size in cold-formed C-profile has been considered as design variable. Linear convolution of criteria, namely minimization criterion of design area of stiffener cross-section and maximization criterion effective area of stiffener cross-section which defines it reduced load-bearing capacity due to flexural buckling has been used as optimization criterion. The parametric optimization problem has been solved using the method of objective function gradient projection onto the active constraints surface with simultaneous correction of the constraints violations. In order to realize the formulated optimization problem, software OptCAD intended to solve parametric optimization problems for steel structural systems has been used. Optimization results of the single edge folds for the cold-formed С-profiles manufactured by «Blachy Pruszyński» company, «BF FACTORY» company as well as «STEELCO» company have been presented by the paper. The results of the performed investigation can be used as recommendations for companies-manufacturers of the cold-formed profiles, as well as a guide for creation the national assortment base of the effective cold-formed profiles promoting wider implementation of cold-formed steel structures in building practice.

To prevent the occurrence of temperature cracking, the induced joints of dams are typically arranged to reduce the tensile strength and orderly guide the crack to form at an induced joint, which can protect the dam structure. The state of the joint surface and the equivalent strength and arrangement of the induced joints have important practical significance for preventing the disorderly cracking of the dam. In this study, the concrete strength, inducer spacing, and concrete age were considered as variable conditions to perform axial tension tests on roller compacted concrete (RCC) bidirectional induced joints. A finite element software was used for numerical simulation, and the simulation results were compared with the experimental results. The equivalent strength of the RCC induced joints increased with the spacing of the induced joints, but the rate of increase gradually declined. The equivalent strength of the RCC induced joints rapidly increased in the early stage, but the strength weakening degree was different at different concrete ages. The strength weakening degree of the induced joint section decreased as the concrete strength increased. These results provide a reference for the setting of induced joints in practical engineering.

Variants of the rotation frequency stabilization of a promising vertically axial wind-driven power plant consisting of a doubly connected stator and a rotor with blades are considered. The stator as a whole is part of the construction, axisymmetric with the rotor, and the rotor is slightly buried in the upper part of the stator — the bell. This plant can be included as an element in a complex power plant for additional and emergency power supply of both stationary and mobile objects, for example, surface robotic systems. The paper proposes to use an aerodynamic method of the rotor angular speed stabilization by controlling the positions of two variable design elements of the plant with respect to its stator. As such elements, a lower guide structure (one of the stator elements) and an aerodynamic brake flap can be used. The rearrangement of both elements positions relative to the stator changes the effective cross section for the interaction of the wind flow entering the installation with the rotor. The method of controller synthesis by the angular speed of the rotor rotation is considered in detail. A feature of this controller is the presence of two control channels with one state variable. First, it is necessary to determine the dynamic ranges of torque control on the rotor shaft for each of the variable geometry elements. This allows to correctly select the switching condition between the two control channels depending on the degree of deviation of the desired flow rate from the current speed. Based on the second-order control error equation, the desired control law of the angular rotor speed is obtained. Using the example of the problem solving of angular speed stabilization with given quality criteria, we simulated a synthesized control system for various initial data. It is shown that the constructed controller is capable of effectively countering the influence of wind disturbances in a wide range of deviations of the current speed from the frequency desired for a given target value.

Abstract Background In a White Paper published in 2019, SHEA describes “The role of electronic health record and ‘add-on’ clinical decision support systems to enhance antimicrobial stewardship programs.” Modifications of the electronic health record and add-on clinical decision support systems are compared and contrasted. Some disadvantages of modification of the EHR include the need to include all end-user affiliates in modifications, lack of order set utilization, and heavy demands of IT staff to modify the EHR. We have utilized alternative alerts which may be customized to individual affiliates and are relatively easy to build which fire when specific medications are ordered (whether within order sets or not) and guide clinicians to more appropriate antibiotic choices. Methods From an antimicrobial stewardship perspective, alternative alerts are activated during the ordering of antibiotics for which routine use is discouraged (e.g., carbapenems, fluoroquinolones). When a provider enters an order, the alternative alert will pop up. The alert consists of two sections: an alert section describing the reason for the alert and a list of therapeutic options for the targeted drug; and links to orders for alternative antibiotics/combinations. The alerts may be configured to allow or not allow the orderer to continue with the original order. Different alternative alerts can be created and used at different facilities using the same EHR platform. We designed alternative alerts for fluoroquinolones, carbapenems, and fifth-generation cephalosporins that allowed providers to continue with the original order. We tested their impact on antimicrobial prescribing for 18 months after implementation, measured as quarterly days of therapy (DOT)/1000 pt-days. Results We noted marked reductions in quarterly DOT/1000 pt-days for fluoroquinolones (-70%) and fifth-generation cephalosporins (-90%). The impact on carbapenem prescribing was more variable. Conclusion Alternative alerts represent an easily created, customizable means to guide providers’ antimicrobial selections. We plan to incorporate more alternative alerts into our antimicrobial ordering process and strengthen the alert for carbapenems. Disclosures All authors: No reported disclosures.

<p><strong>Abstract.</strong> In recent years, the generative process of building information modeling (BIM) digital models oriented to the digitisation of heritage buildings has been supported by the development of new modeling tools, able to integrate the point cloud data produced by laser scanning and digital photogrammetry in major modeling software applications such as Autodesk Revit and Graphisoft Archicad. Architectural and structural elements of churches, castles, and historical monuments such as complex vaults, arches, decorations and ornaments, irregular walls with a variable section and wall stratigraphy require higher levels of detail (LOD) and information (LOI) than new buildings. Consequently, the structure of a BIM model oriented to represent heritage buildings (HBIM) required the definition of a new digital process capable of converting the traditional techniques to the generation of 'unique' digital models able to connect different type of information. Consequently, the generation of 'new' 3D objects able to follow the constructive logic of the detected artefact has required the establishment of new grades of generation (GOG) and accuracy (GOA) to reduce the time and cost of the scan-to-BIM process. The main challenge of this research was the integration of these new modeling requirements in BIM software through the development of an add-in for one of the most used BIM software (Autodesk Revit). Through the generation of the complex vaulted system of the Basilica of Collemaggio (L’Aquila, Italy) and one of the most famous monuments of northern Italy (Arch of Peace in Milan, Italy), the following research shows how it was possible to support users in the HBIM generation, reducing the modeling impact of complex shapes from point cloud data and increasing information sharing for different BIM-based analysis, disciplines and users.</p>

Currently, in most cases, the study of the operability of hydraulic cylinders in terms of their bearing capacity is carried out by means of assessing the longitudinal stability of a compressed rod with the variable cross section. In this case, the inclination of the rod in space is not taken into account. However, during operation, as a rule, a hydraulic cylinder inclined in space due to longitudinal-transverse loading is deformed in the vertical longitudinal plane with the appearance of a full-scale deflection. So, the limit value of the longitudinal compressive force is less than the limit compressive force of a stable rod, which implies that a rod having an initial curvature is more susceptible to bending, appearance of residual deformations in its elements and has less reliability than a straight, vertically arranged one. As the guide elements of the hydraulic cylinder wear out, its total deformation increases, which leads to an increase in longitudinal-transverse loads. With regard to long-stroke hydraulic cylinders, a special danger is their immediate stop in space when the working equipment of the machine meets an insurmountable obstacle. The purpose of the study is a scientifically based description of the areas of functioning of the hydraulic cylinder in the conditions of longitudinal-transverse bending or stability, as well as the boundaries separating them

In order to study the fragmentation energy dissipation characteristics of cemented sand specimens under confining pressure and impact loads, the energy consumption of cemented sand specimens was analyzed through an impact compression and split test performed at different loading rates with different impact pressures by using a variable cross section SHPB (split Hopkinson pressure bar) with an active confining pressure loading apparatus. The results show that (1) the absorbed energy and incident energy were in a linear relationship and the proportion between them was relatively constant under confining pressure, and the absorbed energy had a quadratic relationship with the incident energy under zero confining pressure. (2) The fracture energy ratio increased with the increase in incident energy, the damage energy ratio decreased with the increase in incident energy, and the damage energy ratio were always higher than the fracture energy ratio under confining pressure. (3) The energy absorbed by the cemented sand specimens decreased sharply with the increase of confining pressure under the same incident wave energy conditions, and the reflected wave energy and transmitted wave energy increased. (4) When the incident wave energy was constant, the ratio of the energy causing surface fractures to the energy absorbed by the cemented sand specimens decreased sharply with the increase of confining pressure, while the energy causing crack growth and damage increased sharply. These conclusions may guide similar models of blasting tests in the future.

Seismic imaging in salt geology is complicated by highly contrasted velocity fields and irregular salt geometries, which cause complex seismic wavefield scattering. Although the imaging challenges can be addressed by advanced imaging algorithms, a fundamental problem remains in the determination of robust velocity fields in high-noise conditions. Conventional migration velocity analysis is often ineffective, and even the most advanced methods for depth-domain velocity analysis, such as full-waveform inversion, require starting from a good initial estimate of the velocity model to converge to a correct result. Nonseismic methods, such as electromagnetics, can help guide the generation of robust velocity models to be used for further processing. Using the multiphysics data acquired in the deepwater section of the Red Sea, we apply a controlled-source electromagnetic (CSEM) resistivity-regularized seismic velocity inversion for enhancing the velocity model in a complex area dominated by nappe-style salt tectonics. The integration is achieved by a rigorous approach of multiscaled inversions looping over model dimensions (1D first, followed by 3D), variable offsets and increasing frequencies, data-driven and interpretation-supported approaches, leading to a hierarchical inversion guided by a parameter sensitivity analysis. The final step of the integration consists of the inversion of seismic traveltimes subject to CSEM model constraints in which a common-structure coupling mechanism is used. Minimization is performed over the seismic data residuals and cross-gradient objective functions without inverting for the resistivity model, which is used as a reference for the seismic inversion (hierarchical approach). Results are demonstrated through depth imaging in which the velocity model derived through CSEM-regularized hierarchical inversion outperforms the results of a seismic-only derived velocity model.

The article seeks to explore the discourse and linguistic means through which the Introduction section of Research Medical Articles (RMA) achieve their goals. For that purpose, we have analyzed 207 original RMA in Bulgarian and 129 in English. The articles have been excerpted from prestigious Bulgarian and high-ranking impact factor English language journals. Four major rhetorical moves have been found to guide the discourse flow in the Introduction sections in both corpora – Bulgarian Corps (BC) and English-language Corps (EC). These are: Move 1 - Introducing the general topic; Move 2: Move 2 – Transition to specific topic; Move 3: Move 3 – Identifying a gap and Move 4 – Aim of research. In connection with the realization of the rhetorical objectives of the Introduction section, basic lexical means have been identified and presented. We used the concept metaterm introduced by Mavrodieva and Tisheva (Mavrodieva and Tisheva 2014). We divided the metaterms into general and specific. It has been proven that a certain type of polysemous nouns are of particular importance in the medical context and can therefore be considered as specific metaterms. In both corpora, a number of variable and unchangeable parts of speech have been discovered that are typical of the RMA. Essential to the cohesion and coherence of texts are the so-called high-frequency words: nouns, verbs, adjectives, prepositions, adverbs, collocations and colligations. Regarding Tense and Voice, it has been pointed out that in line with the tradition of the Bulgarian scientific discourse community, the main tense is the so-called Generalized Present Tense (Uslozhneno segashno vreme), whereas in the English-language Corps these are Present Simple and Present Perfect. As for Voice, the BC articles make use mostly of Active Voice, while Passive Voice is used to refer to problems in focus and with impersonal constructions. A peculiar feature of scientific texts in Bulgarian is the use of reflexive verbs with the particle se. The specificity of the sentence structure in the Introduction includes the so-called in Bulgarian linguistics “complicated simple sentences”, including many pre and post modifiers, heavy complementation, as well as compound and complex sentences. Some of the most important discursive elements of this section of RMA are also analyzed. The comparison is direct between the two corpora, and the elements under scrutiny cover such aspects of discourse as hedging and, discourse markers (DM). With regard to the first element, hedging, from a theoretical point of view, it is important to emphasize that hedge structures are a form of the author's Ethos and identity, its degree of presence in the text. We have noted the role of DM as linking devices in the text, marking the boundaries of Steps and Moves in the RMA and indicating a change in the information flow and in the authors’ stance.

Coal and gas outbursts are serious safety concerns in the Chinese coal industry. Mining of the upper or lower protective coal seams has been widely used to minimize this problem. This paper presents new findings from longwall mining-induced fractures, stress distribution changes in roof strata, strata movement and gas flow dynamics after the lower protective coal seam is extracted in a deep underground coal mine in Jincheng, China. Two Flac3D models with varying gob loading characteristics as a function of face advance were analyzed to assess the effect of gob behavior on stress relief in the protected coal seam. The gob behavior in the models is incorporated by applying variable force to the floor and roof behind the longwall face to simulate gob loading characteristics in the field. The influence of mining height on the stress-relief in protected coal seam is also incorporated. The stress relief coefficient and relief angle were introduced as two essential parameters to evaluate the stress relief effect in different regions of protected coal seam. The results showed that the rock mass above the protective coal seam can be divided into five zones in the horizontal direction, i.e. pre-mining zone, compression zone, expansion zone, recovery zone and re-compacted zone. The volume expansion or the dilation zone with high gas concentration is the best location to drill boreholes for gas drainage in both the protected coal seam and the protective coal seam. The research results are helpful to understand the gas flow mechanism around the coal seam and guide industry people to optimize borehole layouts in order to eliminate the coal and gas outburst hazard. The gas drainage programs are provided in the final section.

Background: Timely initiation of breastfeeding is the first step towards achieving recommended breastfeeding behaviours. Delayed breastfeeding initiation harms neonatal health and survival, including infection associated neonatal mortality. Eighty percent of neonatal deaths occur in the low-and middle-income countries (LMICs), where delayed breastfeeding initiation is the highest. Place and mode of childbirth are important factors determining the time of initiation of breastfeeding. In this study, we report the prevalence of delayed breastfeeding initiation from 58 LMICs and investigate the relationship between place and mode of childbirth and delayed breastfeeding initiation in each country. Methods: We analysed data from the most recent Demographic and Health Survey (DHS) and Multiple Indicator Cluster Survey (MICS) collected between 2012 and 2017 and reported by 2019. The study sample comprised all women who had a live birth in the 24 months preceding the survey. ‘Delayed’ initiation of breastfeeding was defined using WHO recommendations as starting breastfeeding after one hour of birth. We coded the stratifying variable for the place and mode of childbirth as “vaginal birth at a facility (VBF)”, “caesarean section birth (CSB) “, and “vaginal birth at home (VBH)”. We used respondent-level sampling weights to account for individual surveys and de-normalised the standard survey weights to ensure the appropriate contribution of data from each country. We report the prevalence and population attributable fractions with robust standard errors. The population attributable risk identifies the proportion of delayed initiation that we could avert among VBH and CSB if everyone had the same risk of delaying breastfeeding as in VBF. Results: The overall prevalence of delayed initiation of breastfeeding was 53.8% (95% CI 53.3, 54.3), ranging from 15.0% (95% CI 13.8, 16.2) in Burundi to 83.4% (95% CI 80.6, 86.0) in Guinea. The prevalence of delayed initiation of breastfeeding was consistently high among women who experienced caesarean section births; however, there was no direct association with each country’s national caesarean section rates. The prevalence of delayed initiation among women who experienced VBF was high in Sub-Saharan Africa and South Asia, even though the CSB rates were low. In some countries, women who give birth vaginally in health facilities were more likely to delay breastfeeding initiation than women who did not. In many places, women who give birth by caesarean section were less likely to delay breastfeeding initiation. Population attributable risk percent for VBH ranged from −28.5% in Ukraine to 22.9% in Moldova, and for CSB, from 10.3% in Guinea to 54.8% in Burundi. On average, across all 58 countries, 24.4% of delayed initiation could be prevented if all women had the same risk of delaying breastfeeding initiation as in VBF. Discussion: In general, women who give birth in a health facility were less likely to experience delayed initiation of breastfeeding. Programs could avert much of the delayed breastfeeding initiation in LMICs if the prevalence of delayed initiation amongst women who experience CSB were the same as amongst women who experience VBF. Crucial reforms of health facilities are required to ensure early breastfeeding practices and to create pro-breastfeeding supportive environments as recommended in intervention packages like the Baby-friendly hospital initiative and Early essential newborn care. The findings from this study will guide program managers to identify countries at varying levels of preparedness to establish and maintain a breastfeeding-friendly environment at health facilities. Thus, governments should prioritise intervention strategies to improve coverage and settings surrounding early initiation of breastfeeding while considering the complex role of place and mode of childbirth.

Background: Patellar dislocations are common among youth athletes. A detailed understanding of patellofemoral anatomy is critical to determine patient prognosis and guide treatment and decision making. Recent literature suggests that measures of patella position relative to the trochlear groove may help identify individuals at risk of repetitive dislocations. While these measures were described using MRI, it is plausible that ultrasound imaging can be utilized to provide similar information in a more cost-effective and time-efficient manner. Purpose: To determine intra and inter-rater reliability of two newly described ultrasound-based measures of patella positioning within two novice examiners. Methods: Subjects were seated with the limb supported in full knee extension and neutral rotation. (Figure 1a) The examiners independently gathered all images and were blinded to each other’s measures for the duration of the study. The transducer was positioned transversely, on the anterior aspect of the knee such that the lateral trochlear ridge, center of trochlear groove, and proximal portion of the patellar tendon were all visible in cross-section. (Figure 1b) Two linear measures were obtained, representing the distance from midpoint of the patellar tendon to a) the center of trochlear groove (MPT-CTG) and b) the lateral trochlear ridge (MPT-LTR). Reliability was assessed using intraclass correlation coefficients (ICC). The average of two measures were used for data analysis. There was a minimum of 1 week between assessments for those subjects with repeated testing. Results: A total of 11 subjects (mean age 15.3) without history of knee pathology were included. There were no significant differences (p>0.05) in either measurement between limbs with MPT-CTG and MPT-LTR values (mean±sd) as follows: MPT-CTG right 8.4mm ± 3.0, left 8.4mm ± 3.3; MPT-LTR right 12.2mm ± 2.7, left 11.6mm ± 2.3. For reliability analysis, each knee served as a discrete variable, yielding a total of 22 data points for evaluation. Inter-rater reliability (n=22) was moderate to good for both measures, with ICC values of 0.724 and 0.814 for MPT-CTG and MPT-LTR, respectively. Intra-rater reliability (n=10) was good to excellent with ICC values of 0.913 and 0.794 for MPT-CTG and MPT-LTR, respectively. (Table 1) Conclusions: This new measure of patella positioning demonstrated moderate to excellent reliability and may be a practical, cost-effective alternative to MRI. While it is encouraging that the subjects in this sample demonstrated no side-to-side differences in either measure, future research should focus on establishing criterion validity and reliability amongst individuals with patellar instability. [Figure: see text][Table: see text]

The use of elbow or curved pipe in the installation of piping has a loss of pressure (pressure drop) which could lead the power of pump that drive the fluid and decrease the energy efficiency of the system. The pressure drop is caused by the curved shape of the elbow that cause pressure on the outer wall (outter) larger and blocking off the pace of the fluid, and flow pressure losses caused by friction, flow separation and secondary flow. A method that can be used to reduce flow separation and pressure loss in the elbow is by the insertion guide vane. The test model in the form of rectangular elbow 900 with a radius ratio (rc/Dh) = 1.1249 without using a guide vane and number of guide vane insertion one until three guide vanes. With Reynolds number ReDh ≈ 8.6 × 104. The velocity inlet is uniform, the measured variable is static pressure. Static pressure was measured using an inclined manometer. With variation the number of guide vane gives a more effect on the value of pressure drop, the largest pressure drop until 123.35% compared to that without guide vane. The velocity distribution profile on the outlet side becomes more uniform. The magnitude of this pressure drop occurs as a result of the increased flow friction and its secondary flow become smaller.

Abstract Based on the design of the supercritical carbon dioxide (SCO2) centripetal compressor, this paper adopts the orthogonal design test method to optimize the pear-shaped volute, designs the front guide vane with the third-order Bezier curve, and designs the outlet by the equal section method. The numerical simulation calculation and analysis of the design conditions and variable conditions of the SCO2 centripetal compressor are carried out. The results at design conditions show that the isentropic efficiency is 92%, the pressure ratio is 1.21, and the mass flow rate is 195.9 kg/s, which is close to the thermal design and level simulation results; the results of variable conditions show that the efficiency of the SCO2 centripetal compressor-flow and pressure ratio-flow characteristic line is similar to that of multistage axial flow compressor. The supercritical carbon dioxide centripetal compressor designed in this paper meets the design requirements, and its feasibility is proved through numerical simulation.

In this paper, the modifications induced by the presence of an inlet flow nonuniformity on the aerodynamic performance of a nozzle vane cascade are experimentally assessed. Tests were carried out in a six vane linear cascade whose profile is typical of a first stage nozzle guide vane of a modern heavy-duty gas turbine. An obstruction was located in the wind tunnel inlet section to produce a nonuniform flow upstream of the leading edge plane. The cascade was tested in an atmospheric wind tunnel at an inlet Mach number Ma1 = 0.12, with a high turbulence intensity (Tu1 = 9%) and variable obstruction tangential and axial positions, as well as tangential extension. The presented results show that an inlet flow nonuniformity influences the stagnation point position when it faces the vane leading edge from the suction side. A relevant increase of both 2D and secondary losses is observed when the nonuniformity is aligned to the vane leading edge. When it is instead located in between the passage, it does not affect the stagnation point location, in the meanwhile allowing a reduction in the secondary loss.

This study aimed to identify the method of parental treatment and its relationship to social intelligence in a sample of adolescents and adolescents in the town of Beit Hanina. To achieve this goal، the descriptive method was used by applying a questionnaire consisting of two sections، the first section of the methods of parental treatment consisting of (24) paragraphs، and the measure of social intelligence (21) paragraphs، the sample of the study consisted of adolescents and adolescents of the town of Beit Hanina، where they numbered (113). The results of the study found that there are no statistically significant differences at the level of indication. There are no statistically significant differences between parental treatment methods and social intelligence attributable to the variable sex، the variable number of brothers and sisters، the variable age group، the variable of the scientific qualification of the father and the scientific qualification of the mother، but There are statistically significant differences at the level in parental treatment methods and social intelligence due to the change of the person responsible for the adolescent. The study found that the methods of parental treatment were closer to leniency، if the average arithmetic (3.67)، and then the democratic style، and the authoritarian style. The degree of social intelligence was low and averaged 2.30. In the light of these results، the researchers recommended a number of recommendations، the most important of which are: the preparation of awareness programs and guidance for parents by educational specialists to explain the importance of the method used in raising children using the best positive methods and avoiding negative methods that may lead children to a decrease in Social intelligence. To guide the attention of officials in the field of psychological guidance to the importance of social intelligence and methods of parental treatment in the preparation of programs and training courses aimed at developing social intelligence among students، and spreading educational awareness.

A laboratory experimental method and an analysis technique are presented for evaluation of individual film-cooling row flow capacity characteristics. The method is particularly suited to complex systems such as hot section nozzle guide vanes (NGV) with lossy feed system characteristics. The method is believed to be both more accurate and more experimentally efficient than previous techniques. The new analysis technique uses an experimentally calibrated network model to represent the complex feed system and replaces the need for internal loss measurements, which are both demanding and inaccurate. Experiments are performed in the purpose-built University of Oxford Coolant Capacity Rig (CCR), a bench-top, blow-down type facility with atmospheric back-pressure. The design of the CCR is informed by the requirements to assess engine-scale film-cooled components rapidly, accurately, and precisely. Improvements in the experimental method include a differential mass flow rate measurement method (which eliminates the effect of leaks and minimizes the number of rows that must be blanked, ensuring that the internal coupling is as close as possible to the engine condition) and a variable bypass flow which ensures the mass flow measurement nozzle always operates within its calibrated range. We demonstrate the method using two high-pressure (HP) NGV designs: an engine part with relatively uncoupled (in terms of internal loss) cooling rows; and a laser-sintered part with highly coupled cooling rows. We show that the individual-row flow capacity of a high-pressure nozzle guide vane (HPNGV) can be evaluated in the CCR in a single day to a 2σ precision of approximately 0.5% and a 2σ accuracy (bias) of 0.6%. The importance of performing individual-row capacity measurements is demonstrated: failure to scale flow capacity on a row-by-row basis introduces an error of 30% in the engine situation.

ABSTRACT Hepatitis C virus (HCV) can be transmitted from mother to child during pregnancy and childbirth. However, the timing and precise biological mechanisms that are involved in this process are incompletely understood, as are the determinants that influence transmission of particular HCV variants. Here we report results of a longitudinal assessment of HCV quasispecies diversity and composition in 5 cases of vertical HCV transmission, including 3 women coinfected with human immunodeficiency virus type 1 (HIV-1). The population structure of HCV variant spectra based on E2 envelope gene sequences (nucleotide positions 1491 to 1787), including hypervariable regions 1 and 2, was characterized using next-generation sequencing and median-joining network analysis. Compatible with a loose transmission bottleneck, larger numbers of shared HCV variants were observed in the presence of maternal coinfection. Coalescent Bayesian Markov chain Monte Carlo simulations revealed median times of transmission between 24.9 weeks and 36.1 weeks of gestation, with some confidence intervals ranging into the 1st trimester, considerably earlier than previously thought. Using recombinant autologous HCV pseudoparticles, differences were uncovered in HCV-specific antibody responses between coinfected mothers and mothers infected with HCV alone, in whom generalized absence of neutralization was observed. Finally, shifts in HCV quasispecies composition were seen in children around 1 year of age, compatible with the disappearance of passively transferred maternal immunoglobulins and/or the development of HCV-specific humoral immunity. Taken together, these results provide insights into the timing, dynamics, and biologic mechanisms involved in vertical HCV transmission and inform preventative strategies. IMPORTANCE Although it is well established that hepatitis C virus (HCV) can be transmitted from mother to child, the manner and the moment at which transmission operates have been the subject of conjecture. By carrying out a detailed examination of viral sequences, we showed that transmission could take place comparatively early in pregnancy. In addition, we showed that when the mother also carried human immunodeficiency virus type 1 (HIV-1), many more HCV variants were shared between her and her child, suggesting that the mechanism and/or the route of transmission of HCV differed in the presence of coinfection with HIV-1. These results could explain why cesarean section is ineffective in preventing vertical HCV transmission and guide the development of interventions to avert pediatric HCV infection.

The Ghanaian insurance industry is on “life supporting machine” finding it very difficult to attract potential customers to patronize their services. Existing customers are also not loyal at all the reasons am yet to unravel. Individuals as well as organizations lack the interest of investing their scares resources in the insurance industry. Thus managers in this spectrum have to make it a point to constantly seek new ways to improve their services with the strategic intent of “loyalising” the hard won customers. It’s in the light of this that, this study is undertaken to examine whether relationship marketing strategies can be one of the assured ways of developing loyal customers. Again to ascertain how trust influence these relationship marketing strategies and customer loyalty. The population of the study is of some section of insurance subscribers in the greater Accra and central regional part of Ghana. Hypotheses of the study were analyzed using correlation and hierarchical regression analysis. Self-administered questionnaires were distributed to respondents. The researcher theorizes and investigates that there are high positive correlation between the four underlying constructs of relationship marketing and customer loyalty. The results of this study again indicated that all the independent variables (communication, competence, commitment and bonding) have a positive significant impact on (dependent variable) customer loyalty through trust as the mediating variable. Managers are to note that the propensity to create customer loyalty depends on the level of trust they have built with its customers. Thus, the focus should be on investing in the customer’s trust which will subsequently lead to customer loyalty. Management of insurance services are to note that the findings provides a more reliable and empirical measure for describing and evaluating the level of their customer loyal with the services they deliver. It again provides empirical support for strategic decisions in several critical areas of their operations, and above all, provides a justifiably valid and reliable guide for designing workable relationship marketing strategies for creating loyal customers.Originality of this study is proven because it has empirically refined the body of knowledge relating to customer loyalty in the Ghanaian insurance industries.

Introduction: The Indian subcontinent is an endemic zone for diseases like malaria and filaria which alter the size of spleen to a variable extent. In order to identify and examine the spleen accurately, the modes of investigation that are at our disposal are Ultrasonography, Computerised Tomography, Magnetic Resonance Imaging and Radionuclide Scan. Linear dimensions are of limited use as a guide to normal splenic size on CT because the spleen is irregular in shape and is obliquely oriented within the left upper quadrant. A more accurate approach to the assessment of splenic size is the splenic index. Sufficient and reliable data for its normal values are lacking. The objective of the present study was to generate normative data of splenic index which could be used as a research and clinical tool. Material & Methods: It was an open randomized study carried out on 80 adults between 20 to 70 years of age. Spleen was identified in each transverse, coronal and sagittal section image of helical CT scan. Results: The average splenic index, calculated as a product of the three measured linear dimensions of spleen i.e. length, breadth and thickness, in males was 369.89 cm³ and in females 298.61 cm³. The mean splenic index was calculated as 342.62 cm³. Conclusion: The results can be used for evaluating patients with suspected splenomegaly, in certain clinical situations where objective measurement of splenic dimensions and comparison with normal values is required, and in drafting of government policies and programs related to malaria and filaria control where these normal values of splenic index help by identifying populations more susceptible to such infections.

The objective of the study is to contribute to the promotion of NTFPs (Bitter kola, Njangsang and palm wine) by assessing their contribution to the income of marketers in the Mifi division. The study was carried out in the Mifi division in the West Region of Cameroon between January and May 2020. Respondents were drawn from a cross-section of marketers. Data was collected through the administration of semi-structure questionnaires and interview guide as well as direct observations. 81 persons involved in the economic sector in five main markets were identified during the reconnaissance survey, of which 65 were interviewed accounting for 80.24%. Data analysis was carried out using descriptive statistics for processing quantitative data and to generate tables and graphs. Results revealed that every stratum of the community participates in the trade, but the main actors were of the middle age group (45 to 55 years old). Economic analysis revealed that measurement unites for NTFPs in various markets are not standardized and there is a high variation in price between period of abundance and period of scarcity. Wholesalers were able to make an annual benefit of 2 338 900 FCFA, 1 077 400 FCFA and 178 600 FCFA per person from palm wine, bitter kola and Njansang respectively. This benefit was related to the origin of products, thus, the proximity of the supply area of palm wine permitted the concerned persons to meet higher benefit. The benefit observed is this study still includes transportation cost, so in reality, the final benefit is a variable value due to the constant variation (usually little variation) of transportation cost depending on the means of transport. Nevertheless, NTFPs are of real contribution to the income of the Mifi division population, but the supply areas are out of the Mifi division and this implicates some constraints such as high transportation cost, seasonality of products and high variation of sale prices. There is a real need of domestication of species to promote their sustainable management in the actual context of climate change.

Introduction The past decade has seen a burgeoning new field titled “night studies” or “darkness studies” (Gwiazdzinski, Maggioli, and Straw). Key theorists Straw, Shaw, Dunn, and Edensor have spearheaded this new field, publishing a recent flurry of books and other scholarly work dedicated to various aspects of the night. Topics range, for instance, from the history of artificial lighting (Shaw), atmospheres of urban light and darkness (Sumartojo, Edensor, and Pink), street music and public space at night (Reia), the experience of eating in the dark (Edensor and Falconer), walking at night (Morris; Dunn), gendered experiences of the city at night (Hardley; Hardley and Richardson “Mobile Media”, “Mistrust”), and women’s solo experiences of the wilderness at night. Contributing to this new field, this article considers some of the embodied ways mobile media have been deployed in the urban night. To date, this topic has not received much attention within the fields of mobile media or night studies. The research presented in this article draws on a qualitative research project conducted in Australia from 2016-2020. The project focussed on participants’ use of mobile media in urban spaces at night and conducted a specific analysis of pertinent gendered differences. Throughout my iterative and longitudinal research process, I engaged various phases of data collection to explore participants’ night-time mobile media practices, as well as to consider how darkness and the night impact networked practices in ways that speak to the postphenomenological concept of multistability (Ihde Postphenomenology and Technoscience). I highlight the empirical findings through a series of participant stories, exploring salient insights into embodied perceptions of darkness and various ways of co-opting mobile media practices in the urban night. Methods: Data Collection, Interpretation, and Representation My research took place in Perth and Melbourne from 2016-2020. A total of 98 individuals, aged 19 to 67 years, participated. Participants came from diverse backgrounds, including urban and rural Australia, Sweden, America, Ethiopia, Italy, Argentina, USA, and England. They were students, teachers, chefs, unemployed, stay-at-home-parents, miners, small business owners, retired, doctors, and government scientists. They identified across the sexuality and gender identity spectrums. My techniques for data collection were grouped into four main phases: (i) an initial survey; (ii) home visits, which included interviews, haptic experiments, observations, and my own situatedness in participants’ homes; (iii) geo-locative tracking and text messaging; and (iv) online follow-up interviews. The study was open to anyone who lived in Perth or Melbourne, was over 18 years old, and used a smartphone. All phases of the data collection were conducted during the day or at night, depending on participant availability. My focus on darkness and the night, in relation to mobile media, evolved over time. The first question regarding mobile media and the night was posed in 2016 during initial data collection, using an online survey to cast a wide net to gather insights on networked functionality afforded by mobile phones and perceptions of safety and risk in urban and domestic space. Participants frequently referred to the differences between day and night. During home visits and face-to-face interviews in 2017, as well as online interviews in 2020, I sought to gain deeper insights into participants’ sensory experiences of darkness and the night. My interpretation and representation of the data adopts a similar approach as vignettes, which are described by Berry in her book on creative practice and mobile media. For Berry, vignettes are a way of “braiding” (xv) accounts of participant experience together. My particular use of this approach has been published in detail elsewhere (Hardley and Richardson “Digital Placemaking”). Postphenomenology, Multistability, and Mobile Media Throughout this article I frame engagement with mobile media as a particular kind of body-technology relation. As the founder of postphenomenology, Ihde, writes, “technologies transform our experience of the world and our perceptions and interpretations of our world, and we in turn become transformed in this process” (Postphenomenology and Technoscience 44). Ihde adapted phenomenology (from Merleau-Ponty, Husserl, and Heidegger) by shifting away from an essentialist body-subject to non-essentialist contextualisation. As Ihde explains (he uses archery longbows and arrows to make his point), all tools are the “same” in an abstract sense; however, “radically different practices fit differently into various contexts” (Postphenomenology and Technoscience 16). In other words, tools (including mobile media) are never neutral and are always multiple and variable depending on context and practice. All tools are therefore situated and embodied in culturally specific ways. Postphenomenological scholarship can, thus, be said to capture the cultural specificity of all human-technology relations. The following examples help illustrate this defining characteristic of postphenomenology, as distinct from phenomenology. It could be argued that Merleau-Ponty’s phenomenological description of the blind man with his cane is an essentialist notion of what it’s like to experience blindness. On the other hand, Wellner’s postphenomenological description of using a mobile phone describes how the same technology can be used by different people in multiple ways, as people assign different meanings to the technology. This notion is best captured by the term multistability, which suggests each technology has numerous uses, applications and purposes. As Irwin explains, the term multistability—one of Ihde’s central concepts within postphenomenology—conveys the inherent adaptability and mutability of both bodies and media engagement, depending on the context or situatedness of a tool’s use. In the following sections, I first explore embodied perceptions of darkness and the night, and then explore how mobile media have modified participants’ embodied perception of darkness and how it informs their situated awareness of their urban surroundings. In terms of my research, this concerns how mobile media users embody their devices in an array of different ways, especially at night. “Feeling” the Night: Embodied Perceptions of Darkness Darkness, and the night, are not simply about the lack of vision. Indeed, while sensory perception in the dark, such as obscured vision and the heightening of other senses, comes into play, we also encounter the night through an enmeshed cultural relationship of darkness and danger. Shaw describes this relationship in the following way: darkness has been equated with danger: the night was a time when demons, criminals and others who presented a threat were imagined to be present in the landscape. Darkness was thus imagined as a space in which both real and mythical dangers were present. (“Controlling Darkness” 5) Chris, a young gay man living in a medium-sized town close to Melbourne, leaned back in his chair, closed his eyes, and laughed when I asked him if he has ever been scared of the dark. He responded: [Silence] Yeah! I have! Wow, what a funny question. [Laughter] I remember always checking my closet as a child before getting into bed. And the door had to be closed. I could not sleep if the closet door was open. When asked what he thought might be in the closet at night, he laughed again and shared: I have no idea. I don’t think I ever thought it was a person, just the unknown. How funny to think about that now—as a gay man I was scared of what might come out of the closet! [Laughter] Chris’s observation of his habitual childhood behaviour illustrates an embodied cultural imagery of darkness and the role of fear, anxieties and the unknown in the dark. He also spoke of “growing out of” his fantastical fear of the dark as he entered adulthood. This contrasts with what many women in my study described, noting their transition from childhood “fears of the dark” to very real and “felt” experiences of darkness and danger. This opened up a major finding in my research, and uncovered navigational and connectivity strategies often deployed by women in urban spaces at night (Hardley and Richardson “Mistrust”). For instance, Leah (a woman in her late 40s living in Perth), revealed her peripatetic engagement with the (sub)urban night when she described her cycling routes with her 8-year-old daughter. While talking with me via Zoom in 2020, she explained: I have an electric bike—it’s great. I can zip around the city and I have a kid’s seat on the back for my daughter. Sometimes I feel like a hybrid pedestrian—I can switch quickly between being on the road or the footpath. Recently, my daughter asked why we always take the long way home at night. I had to think quickly to come up with a response because I think she’s too young to know the truth. I told her that parks are often empty at night, so if something happens to us then there will be no one to help. In a way that’s true, but really, it’s because as a woman and a child it’s safer for us to remain on well-lit streets. Leah’s experience of the city and her mobility at night are distinctly gendered; she reflects on her experience as a “hybrid pedestrian” in relation to what could happen to her and her daughter if they were to ride through the park at night instead of remaining on the well-lit bike path. Overwhelmingly, the men who participated in my study did not share similar experiences or reflections. Introducing the embodiment of darkness and the night, along with associated fears and anxieties, in a general sense sets the atmospheric scene for a postphenomenological analysis of embodied experiences of the urban night and how users co-opt mobile media functionalities to manage their embodied experiences of the dark. Chris and Leah’s stories both suggest how we “feel” at night has important implications for the practical way(s) in which we engage, navigate and curate our experiences of the dark. In the following section, I consider how mobile devices are literally “handled”, particularly by women in the urban context, to mitigate fears and anxieties of the night. I contend that our embodied experience of the urban night is mediated by, and through, our collective and individual fears, anxieties and perceptions of danger in the dark. Co-opting Mobile Media: Multistable Experiences of the Urban Night Reflecting on his own practices of walking at night, Dunn writes, walking at night, however, offers something different, having the capacity to alter our ingrained, seemingly natural predispositions towards the urban surroundings, and our perceptions along with it. (9) Indeed, the night can offer a “capacity to alter”; however, I suggest that it can also reinforce anxieties and fears of the dark (both real and imagined). As such, walking at night can also reinforce “ingrained, seemingly natural predispositions”. Postphenomenology is useful here, as it offers a way to think through practices of what Ihde calls “amplification” and “reduction” of the corporeal schema. Through both actions, mobile media users habituate themselves or take up residence in the urban night by and through their use of smartphone functionalities, as well as their sense of networked connectivity. In the context of this article, the corporeal schema undergoes an amplification and reduction via the co-opting of mobile media, such as an embodied sense of networked connectivity or a tactile prop, to generate a “tele-cocoon” (Habuchi), “shield” (Verhoeff), or “bubble” (Bull Sounding). The corporeal schema can be understood as our lived experience of the world (Merleau-Ponty), whereby our “perceptual reach and bodily boundaries, is always-already extendible through artifacts and technologies” (Hardley and Richardson “Mistrust”). The digital cocoon afforded by mobile media is often gendered and overtly concerned with issues of personal safety and privacy, especially at night. For many women, generating an imagined boundary between the self and others in shared urban spaces is an important function of mobile media. As one Perth participant reflected, my phone’s a good distraction when I’m alone in a public place, especially at night if I’m waiting for someone. Sometimes guys will come up and try to start a conversation—it’s so annoying. If I focus on my phone, it’s like telling them to leave me alone. This tactical use of mobile media to carve out one’s own space in crowded social places was especially common among the women I interviewed. Yet, such practices are also deployed by men, albeit for different reasons. In Melbourne, Dane described the strategic use of his mobile phone as both a creative tool of connection and a means of communicating—especially to women at night—that he was non-threatening. As a proud late-adopter of smartphones, he explained to me that his main reason for buying one had been the camera function; he refers to his smartphone as “a camera that rings”. He particularly enjoys taking photos at night, during which time his familiar streets become “moody and strange”. He spends many hours walking in his neighbourhood, capturing shadows and uploading the images to his public Instagram account. Referring to his dark skin and shaved head, he joked, “I’d look great in a line-up” and added: sometimes I feel a bit self-conscious on the bus or train, particularly late at night, I think maybe I could seem like a threat or something. So, I’ll play a game or chat to friends about my photos via Instagram. I figure it works both ways—I don’t notice anyone and people don’t notice me. As these participant stories reveal, the personal privacy bubble offered by our mobile devices is co-opted differently. Turning to Ihde’s notion of multistability, these examples can be analysed and understood as mobile technologies’ potential variabilities with multiple outcomes (Ihde Postphenomenology and Technoscience). To explore and explain this further, I consider the following participant story in which Britta, an American living in Melbourne, reflected on her night-time pedestrian practices across two cities, sharing: at night, in Australia, my phone would be in my bra. In Philadelphia, it would be in my hand. It's totally different because of safety. When at University in the U.S., I would always talk to a friend while walking from one place to the next. It doesn't even cross my mind to do that in Australia. In Philadelphia, I would call one of the girls I lived with and if someone approached me, I could say, "Oh shit, I'm about to get mugged, this is where I am” and they could call the cops. It's a sense of being on guard. I would never walk using headphones in Philadelphia. In Australia, if I go running at night I listen to music with one earphone in. In this vignette, Britta has habituated an acute awareness of her corporeal schema. As Wellner suggests, “the world is always a negotiation between humans and their tools, their artifacts, their technology, and their devices” (5). In this context, Britta has an amplified awareness of her situatedness, and uses her mobile phone to listen to music in different ways depending on her geographical location. There is a direct connection to her use of headphones to listen to music and her embodied perception of personal safety at night. Turning to Ihde, this participant story can be explained through the term “non-neutrality”, which describes how “no technology is ‘one thing,’ nor is it incapable of belonging to multiple contexts” (Ihde Technology and Prognostic 47). Such an example points to the non-neutrality of mobile media, and how “our perception and environment are mediated by the technology” (Wellner 15). This analysis can be extended further to consider the use of headphones (as an extension of the mobile phone) and geographical location in relation to the concept of multistability—that is, the specificity of use. As Irwin writes, “how is it to be an earbudded body in the world? ... Earbuds are non-neutral and they are becoming deeply imbedded in daily life” (81). Indeed, Bull’s influential work on how personal stereos and iPods change users’ experiences of public spaces (Sound Moves) is useful here in understanding the background of what Irwin refers to as “keeping sound in and sound out” (81). It is, according to Irwin, “about privacy and isolation” (81); however, as Britta’s vignette shows, mobile media practices of privacy and isolation in urban spaces can be impacted by geographical location and urban darkness, and are also distinctly gendered. Applying the concept of multistability allows me to consider how, in some instances, mobile phones are often deployed as a proxy Do Not Disturb sign when alone in public (Hardley and Richardson “Mistrust”). While, in other instances, one’s embodied experience of being an earbudded body in the world can increase their perceptual sense of risk based on various factors, such as geographical location. Beyond this, it also speaks to the relational ontology between body and technology and the mutability of perception. In Britta’s example, her corporeal schema in the urban night is amplified by and through her personal and situated embodiment of mobile media use, particularly her decision to use headphones in specific ways depending on her geographical location. In 2017, I conducted a home visit with Dominique, a woman in her 30s living in Perth. During this visit, she reflected on her use of a Bluetooth earpiece, especially at night, sharing: I use a Bluetooth earpiece to talk over the phone. I also sometimes wear it at night even if I'm not on the phone or expecting a call as I can quickly request that Siri call someone for me without having to actually dig out my phone, unlock it and make the call. I prefer having my hands free. It can make me feel safer at night. Dominique’s description of having her mobile phone on standby can be understood as a habituated practice to overcome her anxieties of being alone at night in urban space, as well as to apprehend her sensory experience of the urban night by remaining “hands free”. Similar to Britta, Dominique’s embodiment in the urban night had become habituated and sedimented over time—or, in other words, “[a] force of habit” (Rosenberger and Verbeek 25). In this way, Dominique’s embodiment is configured depending on her contextual specificity, such as being alone in public spaces at night. Conclusion This article contributes to the emerging interdisciplinary field of “night studies” and “darkness studies” by focusing on the relationship between mobile media practices and the urban night. I based my methods, including data collection, interpretation and representation, in a postphenomenological framework, and detailed how this framework is useful in reflecting deeply and critically on mobile media use at night. Drawing from the framework’s key concept of multistability, I suggest a particular analysis of how users co-opt mobile media functionalities in situationally unique and personal ways in the urban night. The ways in which users co-opt these functionalities are often gendered. I unpacked how some of my research participants deploy mobile media functions as a means of managing their fears and anxieties of darkness and the urban night, and suggest that such uses are always dependent on the users specific situatedness, both within urban spaces and toward other city dwellers. 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