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Introduction
Published in M Rashad Islam, A K M Monayem H Mazumder, Mahbub Ahmed, Engineering Dynamics, 2022
M Rashad Islam, A K M Monayem H Mazumder, Mahbub Ahmed
There are several types of unit systems. Two are very popular and are discussed here:US Customary System (USCS) Units or FPS Units: In the US, length, mass, and time are expressed in feet (ft), pound-mass (lbm) or slug, and second (sec), respectively. FPS means foot-pound-second. Unit of mass is also used as slug (pound-mass), which is pound divided by the gravitational constant (g = 32.2 ft/sec2). More clearly,slug or lbm=lbfftsec2Unit of force is used as lbf or lb. Therefore, one must distinguish the pound-force (lbf) from the pound-mass (lbm). The pound-force is that force which accelerates one pound-mass at 32.2 ft/sec2. Thus, 1 lbf = 32.2 lbm.ft/sec2. In summary, lbf is written as lb and lbm is written as slug.System of International (SI) Units: To maintain consistency worldwide SI units are proposed. In this system, length, mass, and time are expressed in meter (m), kilogram (kg), and second (sec), respectively. The conversion factors for major parameters used in dynamics from SI units to USCS units are listed in Table 1.2.
Units and Significant Figures
Published in Patrick F. Dunn, Fundamentals of Sensors for Engineering and Science, 2019
In the English Engineering system there are pounds of force and pounds of mass, which are designated by lbf and lbm, respectively. In the Technical English system there is only one pound, the pound-force, which is designated by lbf. In that system, a slug is the unit of mass.
Units and Significant Figures
Published in Patrick F. Dunn, Michael P. Davis, Measurement and Data Analysis for Engineering and Science, 2017
Patrick F. Dunn, Michael P. Davis
In the English Engineering system there are pounds of force and pounds of mass, which are designated by lbf and lbm, respectively. In the Technical English system there is only one pound, the pound-force, which is designated by lbf. A slug is its unit of mass.
Comparison between guide plate navigation and virtual fixtures in robot-assisted osteotomy
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Qing Yang, Xisheng Weng, Chunjie Xia, Chao Shi, Jixuan Liu, Chendi Liang, Yanzhen Liu, Yu Wang
Current research has studied the application of guide plates and VFs in orthopedics. However, there has no comparison of the accuracy between two robot-assisted plane cutting methods under the same system. Therefore, we conducted the comparison and analyzed the results based on the same robot and navigation system. The first method is a new robot-assisted GPN, by attaching the guide plate on the end of the robotic arm; together with the 3-D planning, it can quickly position the plate to the planned area and complete the plane cutting. The other method combines the admittance control with VFs. It uses a six-component force sensor to achieve human-robot coordination. Compensate the force applied to the end effector collected by the ATI sensor (Type ATI Gamma, USA, Sensitivity: 1/640 lbf in Fx, Fy and 1/320 lbf in Fz). The compensated force is used as the input of the admittance control function to realize compliance control. And add the VFs constraint algorithm based on this control, and apply the integrated algorithm to complete the bone cutting of the Sawbones.
Device profile of the Orchid safety release valve for the prevention of accidental catheter dislodgement
Published in Expert Review of Medical Devices, 2023
Stress testing measured exerted forces on 371 SRV devices for directional opposition (tension variations applied to x, y, and z directions), against the IV securement, and for differing pull speeds. The Lab testing revealed that IV catheters dislodge with minimal pull pressure within a range of 1 to 8 lbf based on tension in current published literature [19]. The speed the IV tubing was pulled had a marginal difference in preventing dislodgement. Pulling more slowly resulted in higher separation forces. IV dislodgement was prevented by 88.3% by pulling slowly at 20 in/min. Moving more than four times faster, at 94 in/min, resulted in an IV dislodgement prevention of 95.6%. The SRV prevented IV dislodgements by 91.9% across various scenarios and all test groups in which the device separated, with no occurrences of device dislodgement. The average separation force was 3.25 lbf, within the established regulatory required force range of 1–4.2 lbf, with a standard deviation of 0.36 lbf. Final separation forces for all dressing and securement testing with the true functional window ranged from 2.09 lbf to 4.2 lbf.
Entropy-based adaptive design for contour finding and estimating reliability
Published in Journal of Quality Technology, 2023
D. Austin Cole, Robert B. Gramacy, James E. Warner, Geoffrey F. Bomarito, Patrick E. Leser, William P. Leser
The response of interest, y, is the maximum contact force, with a threshold of 2,800 lbf. Thus, to estimate we define The computer model requires 18 hours on 10 cores to produce one sample, severely limiting our ability to entertain a large campaign. We budgeted N = 200 runs for the adaptive design (including an initial LHS of 40), with adaptive samples generated in batches of 10 so the required simulations could be performed in parallel. For the GP surrogate we use the Matérn 3/2 (Stein 2012) kernel with separable length scale and a jitter of The data is prescaled to using bounds derived from five standard deviations away from the mean in each dimension.