Magnitude Angle Research Articles

The Influence of Slipface Angle on Fluvial Dune Growth

AbstractDunes dominate the bed of sandy rivers and they respond to flow by changing shape and size, modifying flow, and sediment transport dynamics of rivers. Our understanding of and ability to predict dune adaptation, particularly dune growth and decay, remain incomplete. Here, we investigate dune growth from an initial flatbed in a laboratory setting by continuously mapping the 3D bed topography using a line laser scanner combined with a 3D camera. High‐resolution profiles of flow velocity and sediment concentration providing both bedload and suspended sediment fluxes were obtained by deploying Acoustic Concentration and Velocity Profiler technology. Our analysis reveals that the magnitude of the dune slipface angle, which determines flow separation and controls turbulence production, adjusts to the imposed flow at time scales similar to the evolution of dune height and length. The initiation of a flow separation zone intensifies through scour, and results in acceleration of the dune growth. Gradients in sediment transport and the rate of dune growth are inherently linked to spatial variations in slipface angles. During dune growth, the slipface angle evolves differently than the ratio of dune height to length, which immediately reaches its equilibrium value after dune initiation.

Tunable Mid-Infrared Optical Properties of Monolayer Black Phosphorus Through Au Nanotriangle Arrays via Electric Field Reflection and Surface Plasmon Polaritons

A metamaterial system composed of monolayer black phosphorus and Au triangle arrays is designed. Absorptivity, transmittivity, and reflectivity are investigated in mid-infrared regime. A low transmissivity and high absorptivity can be obtained via surface plasmon polaritons at the black phosphorus and Au triangle array interface. By changing the geometrical parameters, such as angle magnitude and slit width of Au triangle, we can modulate the transmissivity, reflectivity and absorptivity properties. Different from other previous work, it is found the zigzag direction has a better photoresponse than that armchair by changing the slit width. The electric field of the external radiation field is reflected at the Au triangle edges. Thus, electric field component perpendicular to the polarization direction generates, which can also lead to surface plasmon polaritons and is not researched in others’ work. With increase in the angle of Au triangle, transmittivity (or absorptivity) for armchair direction has a blue shift and for zigzag direction has a red shift. The transmittivity decrease ( or absorptivity increase ) for special wavelength caused by the surface plasmon polaritons may be applied to design filter devices.

Studying the Shape Variations of the Back, the Neck, and the Mandibular Angle of Horses Depending on Specific Feeding Postures Using Geometric Morphometrics.

Simple SummaryMany feeding devices such as hay nets are used to increase the time horses spend feeding on hay. However, when hay nets are used, the horse is often forced to keep unnatural feeding positions. Geometric morphometrics was applied to describe the shape variations of back and neck postures as well as the variations of the mandibular angle according to specific positions adopted during hay feeding: on the ground—control position (CP); neck held 15 ± 3° below withers height with low hay net position (LP); neck held 15 ± 3° above withers height with high hay net position (HP). Our results showed that the back and neck postures as well as the mandibular angle were different in HP compared to CP. Moreover, LP showed that the back posture more closely resembled the shape exhibited by horses feeding from CP; however, no similarity was recorded for neck posture and mandibular angle. Our findings suggest that more attention should be paid when horses keep an unnatural feeding position in comparison to when hay nets are used, since the back and neck postures as well as the mandibular angle can be altered especially when horses are forced to eat with a neck held at 15 ± 3° above the withers.The effects of specific feeding positions upon the horse’s shape variations of the back and neck postures as well as the variations of the mandibular angle have never been objectively studied. For this reason, geometric morphometrics was applied. Six horses, aged 14 ± 8 years (mean ± standard deviation, SD), were video-recorded while using three different feeding positions: on the ground—control position (CP); neck held 15 ± 3° below withers height with low hay net position (LP); neck held 15 ± 3° above withers height with high hay net position (HP). Data were analyzed using principal component analysis (PCA), multivariate analysis of variance (MANOVA), and partial least squares (PLS). A mixed model procedure was applied to evaluate differences in the magnitude of the mandibular angle. Whilst differences between individual horses were confirmed by canonical variate analysis (CVA), PCA analysis showed that a characteristic feeding position could also be identified on a group level. During the HP hay net position, the back and neck postures as well the mandibular angle were different compared to those exhibited by horses feeding from CP. In LP hay net position, the back posture more closely resembled those exhibited while feeding from CP; however, no similarity between LP and CP was found for neck posture and mandibular angle. Since only a few degrees of variation of the feeding position can influence back and neck postures, this aspect should be further investigated. The right compromise between horse welfare, horse safety, and management practices need to be further explored and long-term effects should be investigated.

Long-term stability and condylar remodeling after mandibular advancement: A 5-year follow-up

This study evaluated whether presurgical characteristics, the magnitude of mandibular advancement, and changes in mandibular plane angle are correlated with long-term stability and postsurgical condylar remodeling and adaptations using 3-dimensional imaging. Forty-two patients underwent bilateral sagittal split osteotomies for mandibular advancement using rigid fixation. Cone-beam computed tomography (CBCT) scans were acquired before surgery (T1), immediately after surgery (T2), and at long-term follow-up (T3). The average follow-up period was 5.3±1.7years after surgery. Anatomic landmark identification on the cone-beam computed tomographies and subsequent quantification of the changes from T1 to T2 and T2 to T3 were performed in ITK-SNAP (version 2.4; itksnap.org) and 3DSlicer (version 4.7; http://www.slicer.org) software. Surgical displacements, mandibular plane angle changes, and skeletal stability were measured relative to cranial base superimposition, whereas condylar remodeling was measured relative to regional condylar registration. Partial correlation coefficients were used to assess relationships between clinical and surgical variables, condylar remodeling, and long-term surgical relapse while controlling for variability in the length of follow-up. B-point relapsed more than 2mm posteriorly in 55% of the patients. The only variables strongly associated with the posterior movement of B-point long-term were mesial yaw of the condyle during surgery (P≤0.01) and the length of follow-up from T2 to T3 (P≤0.01). There was no relationship between the magnitude of advancement or presurgical mandibular plane angle and relapse or condylar resorption. Condylar resorption was strongly associated with relapse of B-point in the posterior direction (P≤0.01) and clockwise rotation of the mandibular plane long-term (P≤0.01). Twenty-nine percent of subjects showed resorption of more than 2mm in the inferior direction at the lateral pole, and 17% of the subjects showed resorption of more than 2mm in the inferior direction at condylion. Compared with male subjects, females exhibited significantly greater condylar remodeling (P≤0.01) and slightly greater relapse at B-point (P≤0.05). Surgical relapse at B-point may occur slowly over time and is primarily due to condylar resorption in mandibular advancement patients. Mesial yaw of the condyle during surgery may lead to condylar resorption postsurgically. In addition, females are at greater risk of condylar resorption postsurgically.

Retrospective Analysis on Intraoperative Neuromonitoring (IOM) of Potential Nerve Injury in Scoliosis Correction Surgery

Iatrogenic spinal injury resulting in paraplegia or paraparesis after surgical correction of scoliosis deformity is a rare complication but is very detrimental to the patient. Intraoperative Neuromonitoring (IOM) has become the gold standard to monitor surgical procedures which has potential risks to damage the spinal cord. This study aimed to retrospectively analyze the role of IOM in predicting the severity and extent of neurological injury during and after spinal correction surgery in adult idiopathic scoliosis cases related to surgical variables. This was a retrospective cohort study conducted at Dr. Cipto Mangunkusumo National Central Hospital, Fatmawati Central Hospital, and dr. Drajat Prawiranegara General Hospital during the period of 20 March 2018 to 20 August 2019. The primary outcomes were intraoperative monitoring status and post-operative neurological deficits status. Confounder data on scoliosis correction degree, intraoperative hemorrhage, and type of anesthesia used during surgery were retrieved. Chi-Square statistic was used in the analysis. Out of the ninety three patients eligible for this study, twenty two patients was detected as positive in IOM assessment. Four of the patients were found to be positive for post-operative neuromuscular defect. Thereby it can be concluded that IOM procedure can effectively prevent neurological deficits post-surgery with 81.8% specificity and 95.7% sensitivity among thosepositively detected by IOM. Some of the factors that could potentially influence false positive IOM results such as anesthetic used; dosage and administration procedures; magnitude of the scoliosis correction angle; and amount of bleeding during surgery have to be carefully analyzed.

Hubungan Quadriceps Angle dengan Knee Osteoarthritis di Panti Sosial Harapan Kita

Pendahuluan : Osteoarthritis adalah suatu kondisi sendi yang ditandai dengan kerusakan dan hilangnya kartilago artikular yang berakibat pada pembentukan osteofit, nyeri, pergerakan yang terbatas dan deformitas. Osteoarthritis berperan penting sebagai penyebab utama nyeri dan disabilitas pada lansia. Metode : Penelitian dilakukan dengan pendekatan kuantitatif yang termasuk dalam penelitian analisis. Jenis penelitian ini adalah penelitian non-eksperimental dengan tipe studi korelasi menggunakan uji Pearson dan One Way Anova dengan memaparkan hasil pengukuran sudut Q-angle dengan menggunakan Goniometer dan hasil pengukuran Functional knee dengan KOOS (Kuisioner Injury and Osteoarthritis Score). Hasil : terdapat hubungan linear antara Skor Koos dengan Q Angle, nilai pearson correlation coefficient atau R antarvariabel adalah 0,868 yang berarti kedua variabel memiliki hubungan positif atau berbanding lurus dan sangat kuat. Diskusi : Dari hasil penelitian ini dapat diketahui adanya hubungan yang positif antara fungsional lutut dengan besar sudut Quadricep pada kasus Knee Osteoarthritis serta dapat disimpulkan bahwa semakin besar sudut Q angle maka semakin tinggi nilai fungsional lutut.

Research on the Adjustable Guide Vane in a Compressor Sector Cascade

In order to simulate the inlet flow angle and Mach number of the tested blade, a row of guide vanes is set before the tested blade during the sector cascade experiment. In this paper, a kind of adjustable guide vane (AGV) is designed, which can rotate continuously and change the inlet flow angle of the tested blade conveniently and quickly. The variation rule of the clearance between the AGV and the end wall is introduced. The influence of the clearance on the flow field structure under different Mach number and incidence angle is studied by numerical and experimental methods. It is found that the clearance of the leading edge is small at the top and the root, and the leakage vortex is mixed with the passage vortex. The interaction between the leakage vortex and the passage vortex in the trailing edge results in the decrease of Mach number and the increase of flow angle at the AGV outlet. The clearance has little effect on the span of 20% - 80%. At the same incidence angle condition, with the increase of Mach number, the influence range of leakage vortex is expanded, and the variation magnitude of flow angle and Mach number at the top and root position is increased; At the same Mach number condition, with the decrease of the AGV rotation angle from positive to negative, the top clearance is increased gradually, and the root clearance is decreased gradually. The separation range at the top is expanded gradually, which results in the variation magnitude of flow angle and Mach number is increased, but the effect is opposite at the root of the AGV.

Light deflection angle through velocity profile of galaxies in f(R) model

We explore a new realisation of the galactic scale dynamics via gravitational lensing phenomenon in power-law f(R) gravity theory of the type f(R)propto R^{1+delta } with delta<<1 for interpreting the clustered dark matter effects. We utilize the single effective point like potential (Newtonian potential + f(R) background potential) obtained under the weak field limit to study the combined observations of galaxy rotation curve beyond the optical disk size and their lensing profile in f(R) frame work. We calculate the magnitude of light deflection angle with the characteristic length scale (because of Noether symmetry in f(R) theories) appearing in the effective f(R) rotational velocity profile of a typical galaxy with the model parameter delta approx O(10^{-6}) constrained in previous work. For instance, we work with the two nearby controversial galaxies NGC 5533 and NGC 4138 and explore their galactic features by analysing the lensing angle profiles in f(R) background. We also contrast the magnitudes of f(R) lensing angle profiles and the relevant parameters of such galaxies with the generalised pseudo-isothermal galaxy halo model and find consistency.

Magnetic anisotropy and electrical property of CoZrTaB thin films deposited by oblique sputtering

Soft magnetic materials have been studied extensively in recent years due to their applications in micro-transformers, micro-inductors, spin dependent memories etc. Achieving high uniaxial anisotropy is one of the most important properties for these materials. Oblique angle sputtering without the presence of the magnetic field enables the ease thus lower cost of the adoption of magnetic materials in applications. With a highly soft magnetic material, one can operate the devices made out of these films at giga hertz regions without significant loss of efficiency thus desirable for applications such as power conversion and radio frequency (RF) devices. This work focuses on analyzing different growth conditions of thin films of CoZrTaB and the resulting magnetic and electrical properties of the films. Thin films are grown by oblique-angle sputtering, where the sputtering gun forms an angle with respect to the sample substrate normal, ranging from 0 to 75 degrees. External magnetic field normally applied in order to form magnetic anisotropy is not used during film sputtering process. Using vibrating sample magnetometer, it was observed that films resulting from small oblique angles have no clear magnetic anisotropy developed; whereas in samples deposited at large angles close to 60°, there is clear magnetic anisotropy observed. Scanning electron microscopy imaging of the cross-section of film suggests the formation of tilted columns, which is likely to be the reason for magnetic anisotropy. Resistivity of the films was measured systematically and found to increase as the magnitude of oblique angle during sputtering increased.

Magnetotail Configuration Under Northward IMF Conditions

AbstractDue to the sparsity of space probes, it is still not clear on how the magnetic structure of the magnetotail looks like and how it evolves when the interplanetary magnetic field (IMF) directs northward. This simulation study uses two different global magnetosphere magnetohydrodynamics (MHD) models to simulate two northward IMF events and study the evolution of the magnetotail. Both models show that the magnetotail may form a structure that is composed of a dawnside tail lobe and a duskside tail lobe, under northward IMF conditions with significant By, instead of a northern tail lobe and a southern tail lobe under southward IMF conditions. In this magnetic configuration, a tail lobe extends a domain from northern (southern) cusp to southern (northern) IMF. The larger the magnitude of IMF clock angle, the longer and wider the magnetotail. Such magnetic configuration suggests that magnetotail reconnection is possible to occur when the dawnside tail lobe contacts with the duskside tail lobe and thus a substorm is also possible to occur under northward IMF conditions with significant By.

MANEUVERING PERFORMANCE OF TUGBOAT USING COMPUTATIONAL FLUID DYNAMICS (CFD) APPROACH

Concerning on navigational safety of a ship, comprehensive investigation of manoeuvrability of the ship is prominently required. The turning instability due to improper speed and magnitude of the rudder angle is vulnerable to serious accidents such as collision especially in the confined waters. This paper presents a computational fluid dynamic analyses on manoeuvrability performance of a tug in calm water. Here, the characteristics of the turning ability and zig-zag characteristics of the tug has been assessed due to effect of the various angles of twin-rudder and turning speeds. The results revealed that the increase of rudder’s angle resulted in subsequent reduction of her advance diameter from 144 m, 108 m, 96 m to 92 m. While for zig zag manoeuvre, the first overshoot angle is 0.6° and 1.08° for 10°/10° and 20°/20° rudder’s angle respectively. The first overshoot and second overshoot angle are within the IMO criteria which is below 20° and 25°. However, the increase of turning speed from 7 knots to 9 knots has been proportional with the increase of the turning diameter (advance diameter) from 70 m to 105.2 m. Basically, the turning performances of the tug manoeuvring with the turning speed of 7 to 9 knots incorporated with rudder’s angle 20°, 25°, 30° and 35° have been complied with IMO manoeuvring standards. This preliminary analysis contributes very valuable findings at early ship design stage to provide a safety of the navigational guidance for turning ability of the tug.

Investigation of the effect of several parameters on the applicability of magnetic separation method

Purpose. This research investigates the separation process performed by a magnetic separator. The magnetic separation process is used to isolate ferrous materials from those which are not. Hence, a prototype of a dry magnetic separator is designed. It should be said that this study defines the effect of different parameters (roll speed, magnetic force, and mass of silica sand particle) on separation efficiency. Methodology. The influence of several parameters of the magnetic separator such as magnetic force, centrifugal force, and properties of particle (mass, shape, etc.) were studied theoretically and simulated by SolidWorks software. The optimum conditions of the magnetic separator were obtained, and several trials were performed to find the point that results in a lower effect of roller speed and a higher effect of the magnetic force on the particle in order to achieve higher separating efficiency. Findings. The results show that the centrifugal force are the most important variable influencing separating efficiency. Moreover, it was found that blade angle magnitude of (174) degree with magnetic force between (1.71E-05 to 6.3E-05 N) and roll speed from (84 to 105 rpm) are the optimum separating conditions to reach higher rate of the separating process. Originality. This is the first time that the effect of the gap distance between the magnet and the feeding particles on the magnetic force has been studied. Furthermore, the effect of centrifugal force on magnetic separator force is investigated theoretically and numerically in order to be compared for different parameters. Practical value. The new prototype design of the magnetic separating unit is promising and efficient since the parameters can be varied based on the type and characteristics of materials. It is also revealed that separating time of the materials is reduced. Hence, this type of construction of a magnetic separator is recommended for industrial applications.

The Architecture of a 24 Pulse Dynamic Voltage Restorer for Voltage Enhancement Incorporating Vector Control Methodologies

The whole article is all about the advancement of an improved control system for investigating the compensation functionality of DVRs. To regulate this same switch signal in the voltage-sourced converter, a two-level, 24-pulse DVR is modeled with such an innovative control strategy. Along with order to make sure that P has been reduced, one analysis tries to explain and compares 4 distinct strategies: i.e. Voltage Tolerance Strategy; In-Phase Compensation; Phase Shift Compensation; Voltage Tolerance Strategy The latest model, as well as a control system, would be helpful for more research into PQ in such a distribution network. A detection unit must be fast enough to detect changes in all phase voltages, which would include amplitude, and to trigger the DVR to inject the adequate voltage level with the requisite phase angle magnitude in a short amount of time. To achieve phase and frequency details of the grid voltage and monitor the sag period, a DVR model, as well as a PLL with such a proportional-integral (PI) controller, have been used. This was discovered that only the proposed technique could even accurate deep voltage sag/swell and short interruptions faster than the traditional mechanism. This same proposed computation accuracy has been explained utilizing PSCAD/EMTD modeling on an 11-kV grid whenever the power system is confined to unbalanced three-phase deep voltage sag/swell and short disturbance.

Pengaruh Kuat Arus Dan Besar Sudut Kampuh Terhadap Kekuatan Impact Dan Nilai Kekerasan Plat Baja Karbon Rendah Dengan Menggunakan Las SMAW

Abstract: Welding is welding that utilizes flame heat in electric arcs to melt electrodes and workpieces. SMAW welding is widely used because of its relatively easy to use, cost-friendly and maximum quality results. In conducting welding has several factors that will affect the quality of the welding results such as a welder, welding current and metal distance and welding seam angle. This study aims to determine whether there is an influence of current variations and magnitude of the seam angle to the value of the impact strength and the hardness value of the SMAW welding results. This study uses a pre-experimental method with a one-shot case model. The results of this study indicate the highest impact strength values of current variations in the 80 Ampere specimen at the angle of seam V 60o in the amount of 0.0799 J / mm2 and in the 80 Ampere specimen in the angle of the 80o V in the seam angle of 0.0942 J / mm2. Then for the highest impact strength value variation of seam angle V group of seam angle specimen V 80o current 80 Amperes is equal to 0.0942 J / mm2 and specimen angle of seam V 80o current 100 Ampere 0.0824 J / mm2. The highest hardness value is obtained with a variation of the current specimen group of 100 Ampere in the angle of seam V 60o that is equal to 187.1 HVN and in the specimen group 100 Ampere with the angle of contact V 80o that is equal to 204.4 HVN. Then the highest hardness value variation angle seam V specimen V 80o with current 80 Amperes is equal to 191.63 HVN and specimen angle of seam V 80o with 100 amperes current that is equal to 204.4 HVN. KeyWords : SMAW, Welding current, V groove, Impact Strength, Hardness

Synthesis and Characterization of Polystyrene/CuO-Fe2O3 Nanocomposites from Natural Materials as Hydrophobic Photocatalytic Coatings

This study reports on the synthesis, characterization of polystyrene(PS)/CuO-Fe2O3 nanocomposites, and their application as hydrophobic coatings. CuO and Fe2O3 materials were synthesized from natural materials by the milling method. Meanwhile, the PS/CuO-Fe2O3 nanocomposites were synthesized by the sol-gel method. Furthermore, the hydrophobic coating on the glass substrate was made by the spin-coating. To obtain highest value of contact angle, the composition of both CuO and Fe2O3 in nanocomposite as well as calcination temperatures were varied. Sample characterization was conducted using X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet visible (Uv-Vis) spectrophotometry analysis. The Sessile drop method was used to determine the contact angle of the layer. The results showed that PS/CuO-Fe2O3 nanocomposite was successfully obtained with a crystal size between 40–52 nm and grain size of 92 nm. In addition to the basic material of composites, hematite and tenorite, the presence of copper ferrite phase was also identified. The CuO-Fe2O3 composition and its large calcination temperature also plays an effective role in the magnitude of the contact angle. The highest value of contact angle obtained was 125.46° at 3:1 composition and calcination temperature of 200 °C. We found that the PS/CuO-Fe2O3 composite was hydrophobic, but the photocatalyst activity was very small at 0.24%.

Mathematical Analysis of Voltage Dip propagation in CIGRE (International council of large electric system) Low Voltage Distribution Test Network

Whenever fault occurs at any stage of power system, the magnitude of voltage and phase angle both are changed. In distribution system, there are sensitive loads such as digital computers; motor drives etc are connected with a system. Due to fault conditions, unbalancing in voltage may occur. So it may cause of damaging of equipment. Fault in distribution system may lead to voltage dip in system; it is the big problem of power quality. So it more important to understand the power quality and it is also important to analyze voltage dip propagation when different types of faults occur on system.

Mathematical Analysis of Voltage Dip propagation in CIGRE (International council of large electric system) Low Voltage Distribution Test Network

Whenever fault occurs at any stage of power system, the magnitude of voltage and phase angle both are changed. In distribution system, there are sensitive loads such as digital computers; motor drives etc are connected with a system. Due to fault conditions, unbalancing in voltage may occur. So it may cause of damaging of equipment. Fault in distribution system may lead to voltage dip in system; it is the big problem of power quality. So it more important to understand the power quality and it is also important to analyze voltage dip propagation when different types of faults occur on system.

Mathematical Analysis of Voltage Dip propagation in CIGRE Low Voltage Distribution Test Network

Whenever a fault occurs at any stage of the power system, the magnitude of voltage and phase angle both are changed. In the distribution system, there are sensitive loads such as digital computers; motor drives, etc are connected with a system. Due to fault conditions, unbalancing in voltage may occur. So it may cause of damage to equipment. Fault in the distribution system may lead to a voltage dip in the system; it is the big problem of power quality. So it more important to understand the power quality and it is also important to analyze voltage dip propagation when different types of faults occur in the system. This research paper summarizes the results from a number of different voltage dips investigations and their verification of mathematical calculations. These investigations involve characterizing the voltage dips performance.

Effects of prolonged walking with body borne load on knee adduction biomechanics

BackgroundSoldiers that suffer a service-related knee musculoskeletal injury routinely develop joint osteoarthritis. Knee osteoarthritis is a substantial and costly problem among soldiers, yet it is unknown how body borne load and duration of walking impact knee adduction biomechanics linked to progression and severity of osteoarthritis. Research questionThis study determined the adaptations in magnitude and variability of knee adduction joint angle (KAA) and moment (KAM) during prolonged walking with body borne load. MethodsThirteen recreationally active participants had knee biomechanics quantified while walking over-ground for 60-min at 1.3 m/s with three body borne loads (0, 15, and 30 kg). Magnitude and variability of KAA and KAM measures were quantified and submitted to a RM ANOVA to test the main effect and interactions between load (0, 15 and 30 kg) and time (0, 15, 30, 45 and 60 min). ResultsBody borne load increased peak KAM (p < 0.001), whereas time increased peak and range of KAA (both: p < 0.001). Specifically, peak KAM increased with each addition of body borne load (all: p < 0.025), and peak and range of KAA increased after 30 min of walking (both: p < 0.040). Neither body borne load, nor time had a significant effect on KAA or KAM variability (both: p > 0.05). SignificanceProlonged walking with heavy body borne load increased knee adduction biomechanics related to osteoarthritis. Adding heavy body borne load increased in peak KAM whereas duration of walking increased KAA, knee biomechanics that may increase loading of the medial knee joint compartment and risk of OA at the joint.

Biofuels and its spray interactions under pilot-main injection strategy

An experimental study was performed to explore the effect of pilot and main injection strategy on injection interactions and the spray characteristics of biodiesels that were derived from different feedstocks. Biodiesel considered in this investigation ranged from rapeseed methyl ester, sunflower oil methyl ester, coconut oil methyl ester, waste cooking methyl ester, and tallow methyl ester. The sprays of these biodiesel were characterized through the measurement of macroscopic parameters such as spray penetration, spray angle and spray area, which were compared against ULSD for both pilot and main injection. This investigation was performed in a constant volume chamber maintained under non-reactive conditions. The magnitude of cone angle and spray area for most biodiesel were lower than ULSD. Conversely, the spray tip penetrations for most biodiesels were higher than ULSD. The main injection showed relatively larger magnitude for all macroscopic spray parameters than those of pilot injection. Expulsion of liquid was observed in the dwell period between pilot and main injection as well as end of main injection for all fuels. The end-of-injection expulsions are mainly due to injector needle dynamics rather than variation in physical properties of fuels.