Bulky Objects Research Articles

Prevalence and Biopsychosocial Factors Associated With a Current Episode of Low Back Pain Among Adults With a Previous History of Low Back Pain: A Cross-sectional Study of Market Traders in an African Population

Low back pain (LBP) is the leading cause of years lived with disability globally, with Nigeria having one of the greatest burdens. A current episode of LBP is important in Nigeria, but the associated factors are unknown. This cross-sectional study investigated the prevalence, biomechanical, and psychosocial factors associated with a current episode of LBP among 700 adult market traders with previous LBP in an urban Nigerian population. Descriptive, bivariate, and multivariate analyses were conducted. The prevalence of a current episode of LBP was 76.4%. Factors associated with an increased risk of a current episode of LBP in a decreasing order of importance were exposure to biomechanical factors (aggregate [total] score) (odds ratio [OR] = 1.535; 95% confidence interval [CI] = 1.398–1.685); anxiety (OR = 1.182; 95% CI = 1.089–1.282); fear-avoidance beliefs (physical activity) (OR = 1.139; 95% CI = 1.029–1.261); fear-avoidance beliefs (work) (OR = 1.105; 95% CI = 1.047–1.165); while factors associated with a reduced risk of a current episode of LBP were ability to take breaks in the job in addition to scheduled breaks (OR = .430; 95% CI = .240–.773) and ability to control the order and pace of tasks (OR = .477; 95% CI = .236–.965). Occupational biomechanical and psychosocial factors were associated with a current episode of LBP in logistic regression models explaining 52.7% and 73.1% of the variation in a current episode of LBP. Occupational biomechanical factors, particularly handling large and bulky objects at arm’s length and kneeling and squatting, produced the greatest risk of a current episode of LBP. PerspectiveOccupational biomechanical factors, occupational psychosocial factors, and personal psychosocial factors such as anxiety and fear-avoidance beliefs are associated with a current episode of LBP in Nigeria. Pragmatic public health and occupational health initiatives that modify exposure to these factors may be required in Nigeria.

IOT Empowered Helmets: Pioneering Safety in the Mining Sector

Mining sector is the most prominent to accidents. The accident rate in mining is about 87% .Mining activity involves a lot of tedious and time-consuming tasks as well. Out of the various risks associated with mining there exists many different types of hazardous gases like carbon monoxide, hydrogen sulphide,methane and excess of carbon dioxide. Mining also includes the risk of tremors and landslides as well. Along with that there is the danger of falling of large and bulky objects as well. On top of that removal of helmet is even more dangerous. Moreover ,monitoring each and every miner is also an important factor when it comes to mining. As a result there are lot of risks associated with the same. At times these risks can be life-threatening and result into fatal error .Lifesaving helmet for miners is an IOT based complete protection of miners. As the traditional model of smart helmet doesn’t take all the above mentioned safety threats into consideration our aim through this proposed system is to develop a complete safety equipment in the form of helmet to safeguard miners from the various dangers present in the mining industry.

The significance of sample preparation of historical and contemporary poly(vinyl chloride) objects to investigate the distribution and changes of molar mass by SEC-MALS-dRI

The distribution of molar mass of historical and contemporary poly(vinyl chloride) objects was determined using size exclusion chromatography with multi-angle light scattering detection. The weight average molar mass was determined for a collection of 57 samples, ranging from 75 to 186 kg/mol with a median of 102 kg/mol. Rigid PVC objects were found to have a significantly lower weight average molar mass (Mw = 81 kg/mol) than plasticized ones (Mw = 102 kg/mol). Thin objects also exhibited significantly lower Mw than bulky objects. A substantial presence of aggregates was noted and characterized as an ‘aggregate ratio’ for the entire collection. Heating a solution of poly(vinyl chloride) in THF at 55 °C for 5 h proved successful in the dissociation of the aggregates and allowed for an accurate determination of molar mass. The uncertainty of the Mw determination was statistically evaluated and used to study the effects of accelerated degradation on Mw. No statistically significant changes in Mw were observed in samples artificially aged at 50 °C to 80 °C for up to 15 weeks, indicating that Mw does not decrease during degradation of a PVC heritage object and that accelerated degradation does not lead to polymer crosslinking.

A facile fabrication method of wettability modification of TiAl6V4 based on alkali solution treatment: Superhydrophilic, superhydrophobic and slippery surface

The rapid development of nanoscale surface modification technology has led to the development of superhydrophilic, superhydrophobic, and slippery liquid-infused porous surfaces (SLIPS) in recent decades. These surfaces have excellent self-cleaning and anti-contamination performance, and many studies have reported their industrial applications. Industrial and modern medical applications of titanium are rapidly expanding owing to its advantages of chemical stability, high mechanical strength, stable corrosion resistance, and biocompatibility; however, performing surface modification of titanium remains challenging. In this study, superhydrophilic, superhydrophobic, and SLIPS were fabricated on titanium using a simple surface fabrication method, and their wettabilities were analyzed and compared. Furthermore, we succeeded in applying the method used in this study to bulky and complex objects. Chemical and physical analyses were performed to confirm the fabrication, wettability properties, and nanostructures of the modified surfaces. The simple fabrication method presented a significant advancement as there are no limitations in its application to large areas, complex shapes, or mass production, unlike existing titanium wettability modification methods.

Design and Evaluation of Capacitive Smart Transducer for a Forestry Crane Gripper

Stable grasps are essential for robots handling objects. This is especially true for "robotized" large industrial machines as heavy and bulky objects that are unintentionally dropped by the machine can lead to substantial damages and pose a significant safety risk. Consequently, adding a proximity and tactile sensing to such large industrial machinery can help to mitigate this problem. In this paper, we present a sensing system for proximity/tactile sensing in gripper claws of a forestry crane. In order to avoid difficulties with respect to the installation of cables (in particular in retrofitting of existing machinery), the sensors are truly wireless and can be powered using energy harvesting, leading to autarkic, i.e., self-contained, sensors. The sensing elements are connected to a measurement system which transmits the measurement data to the crane automation computer via Bluetooth low energy (BLE) compliant to IEEE 1451.0 (TEDs) specification for eased logical system integration. We demonstrate that the sensor system can be fully integrated in the grasper and that it can withstand the challenging environmental conditions. We present experimental evaluation of detection in various grasping scenarios such as grasping at an angle, corner grasping, improper closure of the gripper and proper grasp for logs of three different sizes. Results indicate the ability to detect and differentiate between good and poor grasping configurations.

Large‐Area X‐Ray Scintillator Screen Based on Cesium Hafnium Chloride Microcrystals Films with High Sensitivity and Stability

AbstractLead‐halide perovskites have received extensive attention in X‐ray imaging applications recently. However, their poor stability, lead toxicity, and strong light self‐absorption seriously limit the commercial development. Here, we report a vacancy‐ordered Cs2HfCl6 double perovskite for scintillators applications. The Cs2HfCl6 microcrystals (MCs) are characterized by broadband blue emission with a large Stokes shift. Joined experimental‐theoretical characterizations reveal the highly localized charge distribution in Cs2HfCl6 and structural distortion of [HfCl6]2− octahedron in the excited state favor the formation of self‐trapped excitons (STEs), which contribute to the broadband emission. Benefiting from the radioluminescence of STEs with negligible self‐absorption, the light yield of Cs2HfCl6 scintillator reaches 21700 photons/MeV, and the detection limit is 55 nGyair s−1. Additionally, the Cs2HfCl6 scintillator exhibits extremely low hygroscopicity and good resistance to X‐ray irradiation. Further, a large‐area scintillator screen (20×20 cm2) is fabricated by combining scrape‐coating and soft‐pressing techniques, showing a spatial resolution of 11.2 lp mm−1. Given the high spatial resolution and fast light decay of this scintillator screen, static X‐ray imaging of bulky objects is realized, and dynamic X‐ray imaging of a rotating chopping fan is demonstrated without ghosting effects. These results demonstrate the great commercial promise of Cs2HfCl6 scintillation screens for indirect X‐ray detection.

Optimal design of robotic work-cell through hierarchical manipulability maximization

The increasing requests for flexible robotic applications involving the rapid relocation of the robot manipulator , possibly mounted on a mobile base, imposes tolerance to imprecise positioning. The high manipulability of the nominally designed poses, i.e. , the capacity to change the position and the orientation of a given robot joint configuration’s end-effector, is often considered a proxy for robustness to imprecise positioning. This work presents a method for choosing target end-effector poses to manipulate bulky objects in complex environments. The paper proposes a two-layer optimizer connected in cascade to maximize the manipulability and achieve reasonable computational time. First, using a genetic algorithm (GA) allows a global search for a satisfactory solution to the target poses of the task at the same time. Subsequently, the output of the GA becomes the initial guess for the simulated annealing (SA) algorithm, which locally maximizes each pose’s manipulability separately. The feasibility of the connecting trajectories and collisions are checked in both layers. Experiments show the method’s ability to find excellent solutions within a limited time, considering a complex problem involving manipulating large objects in a cluttered environment. The simulations of three working scenarios allowed testing of the proposed method. The final validation of the algorithm was on two relevant industrial use-cases: the manipulation of sidewalls and the manipulation of cargo panels inside an aircraft fuselage . • Optimal robotic workcell design can be a hard problem in some situations. • A tool is provided to optimize the robot position with respect to target poses. • Cascaded optimization allows for fast solutions search in complex environments. • Global optimization of the whole set of tasks followed by single task refinement.

Performance Analysis and Verification of 14-MeV Fast Neutron Radiography

The ability of 14-MeV fast-neutron radiography (FNR) to inspect bulky objects is evaluated. Both analytical and experimental approaches are used for this purpose. Two important performance parameters—spatial resolution and contrast sensitivity—are theoretically analyzed, especially considering the influence of scatter background and noise. The effect of detection quantum efficiency (DQE) on contrast sensitivity of FNR systems is discussed in this article. To verify the results, film-based neutron radiography experiments were performed using a high-intensity D-T neutron source. Iron samples of varying thickness and containing different detectable structures were used. The visibility and detection capability of the objects were compared with corresponding theoretical results. The results show that the spatial resolution is 0.6 mm and the contrast sensitivity is 2.9 mm for a 3-cm-thick sample. The experiments are in good agreement with theoretical results. This provides a theoretical model for fast-neutron system design and performance evaluation.

Оцінка можливості застосування автофажних двигунів в системах відводу космічних об’єктів

This article is devoted ascent depreciation in an earth orbit of space crafts for different functions that allow to solve many problems connected with space activity, in particular, maintenance of wider use of space resources and more effective clearing of a near space from space debris. The last is particularly true for bulky space objects of a technogenic origin which can be deorbit from earth orbits by using the special means for deorbiting injection into the target orbit by launch vehicles. As the ascent of such means for deorbiting by orbital launch vehicle demands significant financial expenses, for their decreased application of easy autophagy launch vehicles with burned fuel tanks is offered. The basic making unit of such launch vehicles is an autophagy engine. The design of autophage engine design and the principle of its operation of the version with compulsory fuel supply to the combustion chamber are presented and the expediency of use of such an engine for small spaceships in case of the impossibility of application of rather heavy usual systems of storage and fuel supply is shown. However, now the weight of the accepted systems of compulsory fuel supply autophagy engines for spaceships remains significant for launch vehicles. As one of the alternative ways of a feed the engine of autophagy launch vehicle, the capability of submission by using the inertia of the most fuel charge is considered. The unit of the autophagy engine contains an evaporator and works in a pulse mode, supplying fuel supply between momentums at the moment of low pressure in the engine. The effect of retardation (easings), representing pressure decrease and engine thrusts in flight time is established. This effect is called by the forces of inertia acting on the sliding engine, and has экспоненциальную an easing picture. Considering the effect of retardation, a system of the equations for calculating kinematic and design data of the launch vehicle with the autophagy engine is offered. The received results of the research have scientific and practical value and can find wide applications in the design of schemes and deorbiting means.

Trajectory Generation of a Quadrotor Transporting a Bulky Payload in the Cluttered Environments

When an aerial robot carries a bulky and heavy payload, it suffers from a wavering effect because of the large inertia of the heavy mass of a payload, which can cause a serious crash or fall to the ground. We propose the path-planning algorithm for an aerial robot to pass a narrow space while transporting a bulky payload to resolve the issue. Unlike the existing conventional path-planning method that treats the payload as a point-mass, this paper generates the trajectory considering the shape of a payload and passage size of an Unmanned Aerial Vehicle (UAV). First, we design a map-generation algorithm with the Voronoi diagram by exploiting the fact that the UAV has an ellipsoidal shape in transport operation with a bulky object. The modified map data can be exploited for the global path generation such as A* path-planner. For the rotational motion of the UAV, the heading angle was determined by considering the lengths of the major and minor axes of the ellipse. The global path was optimized based on the elastic band optimization algorithm to solve the jerky motion on the trajectory. Through the simulations and experiments, we validate the efficiency of our algorithm in the environment with the narrow space. Experimental results showed that the proposed path-planning algorithm could be used for safe aerial transportation in realistic environments.

Hydrogen-Rich 2D Halide Perovskite Scintillators for Fast Neutron Radiography.

A fast neutron has strong penetration ability through dense and bulky objects, which makes it an ideal nondestructive technology for detecting voids, cracks, or other defects inside large equipment. However, the lack of effective fast neutron detection materials limits its application. Perovskites have shown excellent optical properties in many areas, but they are absent from fast neutron detection imaging because they cannot directly absorb fast neutrons and emit luminescence. Here, we demonstrate a hydrogen-rich long-chain organic amine modified two-dimensional (2D) perovskite fast neutron scintillator, Mn-(C18H37NH3)2PbBr4(Mn-STA2PbBr4). Its hydrogen density can reach 9.51 × 1028 m-3, and the photoluminescence quantum yield can reach 58.58%, so it is possible to integrate fast neutron absorption and luminescence into a single compound. More importantly, Mn-STA2PbBr4 can be made into a large-area self-supporting fast neutron scintillator plate with satisfactory spatial resolution (0.5 lp/mm (lp: line pairs)). This strategy provides a simple and promising choice for fast neutron scintillator nondestructive testing.

Building and Infrastructure Defect Detection and Visualization Using Drone and Deep Learning Technologies

This paper presents an accurate and stable method for object and defect detection and visualization on building and infrastructural facilities. This method uses drones and cameras to collect three-dimensional (3D) point clouds via photogrammetry, and uses orthographic or arbitrary views of the target objects to generate the feature images of points’ spectral, elevation, and normal features. U-Net is implemented in the pixelwise segmentation for object and defect detection using multiple feature images. This method was validated on four applications, including on-site path detection, pavement cracking detection, highway slope detection, and building facade window detection. The comparative experimental results confirmed that U-Net with multiple features has a better pixelwise segmentation performance than separately using each single feature. The developed method can implement object and defect detection with different shapes, including striped objects, thin objects, recurring and regularly shaped objects, and bulky objects, which will improve the accuracy and efficiency of inspection, assessment, and management of buildings and infrastructural facilities.

Discovery of davemaoite, CaSiO3-perovskite, as a mineral from the lower mantle.

Calcium silicate perovskite, CaSiO3, is arguably the most geochemically important phase in the lower mantle, because it concentrates elements that are incompatible in the upper mantle, including the heat-generating elements thorium and uranium, which have half-lives longer than the geologic history of Earth. We report CaSiO3-perovskite as an approved mineral (IMA2020-012a) with the name davemaoite. The natural specimen of davemaoite proves the existence of compositional heterogeneity within the lower mantle. Our observations indicate that davemaoite also hosts potassium in addition to uranium and thorium in its structure. Hence, the regional and global abundances of davemaoite influence the heat budget of the deep mantle, where the mineral is thermodynamically stable.

Features of the extraction of foreign bodies from the lower urinary tract

BACKGROUND: Foreign bodies introduced by patients into the bladder and urethra are relatively rare in clinical practice. As a result, there is insufficient information in the scientific literature regarding methods of extracting foreign bodies from the urinary tract.
 AIM: determination of the optimal methods for extracting foreign bodies from the urethra and bladder.
 MATERIALS AND METHODS: Foreign bodies of the lower urinary tract were removed in 21 patients: 15 (71.4%) men and 6 (28.6%) women. Foreign bodies were found in the urethra in 7 (33.3%) patients and in the bladder in 14 (66.7%) patients. Removal of foreign bodies from the urethra and bladder was performed endoscopically or during open surgery.
 RESULTS: Removal of stabbing, cutting and glass objects from the urinary tract in 9 patients was performed during open surgery. Foreign bodies with even smooth edges were removed in 12 patients under urethrocystoscopic control. At the same time, in two patients, coagulated suppositories were first fragmented in the bladder cavity, and then removed in parts. Cystolithotripsy was performed in one patient with a suppository inlaid with calculus before fragmentation.
 CONCLUSIONS: Foreign bodies with sharp edges or made of glass are safer to be removed from the lower urinary tract during open surgery. Foreign bodies with a smooth and even surface are optimally removed endoscopically. Long and bulky foreign objects that can be fragmented in the bladder cavity are best removed in parts. When foreign bodies are encrusted with large calculi, cystolithotripsy should be performed before their endoscopic extraction.

Manipulation Planning for Large Objects through Pivoting, Tumbling, and Regrasping

Robotic manipulation of a bulky object is challenging due to the limited kinematics and payload of the manipulator. In this study, a robot realizes the manipulation of general-shaped bulky objects utilizing the contact with the environment. We propose a hierarchical manipulation planner that effectively combined three manipulation styles, namely, pivoting, tumbling, and regrasping. In our proposed method, we first generate a set of superimposed planar segments on the object surface to obtain an object pose in stable contact with the table, and a set of points on the object surface for the end-effectors (EEFs) of a dual-arm manipulator to stably grasp the object. Object manipulation can be realized by solving a graph, considering the kinematic constraints of pivoting and tumbling. For pivoting, we consider two supporting styles: stable support (SP) and unstable support (USP). Our proposed method manipulates large and heavy objects by selectively using the two different support styles of pivoting and tumbling according to the conditions on the table area. In addition, it can effectively avoid the limitation arising due to the arm kinematics by regrasping the object. We experimentally demonstrate that a dual-arm manipulator can move an object from the initial to goal position within a limited area on the table, avoiding obstacles placed on the table.

Hybrid electrostatic and gecko-inspired gripping pads for manipulating bulky, non-smooth items

We present hybrid electrostatic and gecko-inspired gripping pads that help robots to lift and carry bulky objects. The directional, gecko-inspired adhesive provides a controllable shear force with low normal force, providing a very high effective coefficient of friction so that items like bags full of groceries and heavy cardboard boxes can be lifted using only 1–2 N of squeezing force. The addition of electrostatics helps the pads to conform to non-smooth surfaces, providing substantially higher shear forces than with gecko-inspired adhesives alone. The electrostatic effect is enhanced by doping the silicone rubber adhesive material with calcium copper titanate (CCTO), except at the contacting faces of the adhesive microstructures, where a smooth surface finish is important for adhesion. We describe the multimaterial fabrication process used to create the new hybrid adhesive and present the results of robotic lifting experiments with non-smooth bulky items.

Special Issue on Human–Robot Interaction (HRI)

Human–robot interaction (HRI) is one of the most rapidly growing research fields in robotics and promising for the future of robotics technology. Despite the fact that numerous significant research results in HRI have been presented during the last years, there are still challenges in several critical topics of HRI, which could be summarized as: (i) collision and safety, (ii) virtual guides, (iii) cooperative manipulation, (iv) teleoperation and haptic interfaces, and (v) learning by observation or demonstration. In physical HRI research, the complementarity of the human and the robot capabilities is carefully considered for the advancement of their cooperation in a safe manner. New advanced control systems should be developed so the robot will acquire the ability to adapt easily to the human intentions and to the given task. The possible applications requiring co-manipulation are cooperative transportation of bulky and heavy objects, manufacturing processes such as assembly and surgery.

Improvements in the electromechanical properties of stretchable interconnects by locally tuning the stiffness

Recent advances in materials science and structural design have changed electronic applications from being bulky and rigid objects to small and soft products that have emerged for a wide range of applications, especially human-related products for which mechanical adoption is the key requirement. A typical stretchable application consists of small-sized, rigid IC-chips and passive components interconnected by conductive tracks on soft substrates. The early failure of such devices initiates from the rigid-soft interface due to the accumulation of stress. Therefore, special attention is needed to reduce the strain concentration at the interface. In this paper, stretchable interconnects were fabricated using a screen-printing method and surface mounted devices (SMDs) were bonded using an isotropic conductive adhesive. By partially removing material from the substrate in areas a little way from the rigid components, the stiffness is locally reduced, and this leads to an increase in the local stiffness around the SMDs and hence shields the soft-rigid interface against the stress. Materials can be removed by two different patterns. A finite element analysis and experimental data show 11%–19% improvements in single pull-up tests for the modified samples. This approach makes the electromechanical behaviour independent of encapsulation properties.

Methods of formation of receptor (voxel) geometric models for automated layout tasks

In the framework of design automation, the capabilities of receptor (voxel) geometric models in the tasks of automated layout are shown. Being one of the methods of discrete geometric descriptions of composable objects, they make it possible not only to easily determine cases of their mutual intersection, but also to form intelligent composition algorithms (for example, traces). However, the receptor models are inherently in-machine themselves, which significantly complicates their use. At the same time, modeling composable objects by means of CAD systems (AutoCAD, SolidWorks, KOMPAS, Autodesk Inventor, etc.) presents no difficulty. The article shows the possibility of converting a solid-state model made in any of the existing CAD systems into a receptor one. This allows you to continue using this receptor model as the source for the subsequent operations of computer-aided design layout, taking into account additional factors. In our case, this is the definition of the possibility of delivering bulky objects, among others previously placed, which act as areas of prohibition in our case. The practical value of this study is to assess the possibility of moving super-large cargo along the construction site, assessing the ergonomic design of mechanical, electromechanical, airconditioning and other auxiliary equipment of civil and industrial buildings for ease of installation and subsequent maintenance. An algorithm implemented in the form of a macro CAD-system is described: the formation of a receptor model of a relocatable or assembly equipment based on its solid-state model.

Robust collaborative object transportation using multiple MAVs

Collaborative object transportation using multiple MAV with limited communication is a challenging problem. In this paper, we address the problem of multiple MAV mechanically coupled to a bulky object for transportation purposes without explicit communication between agents. The apparent physical properties of each agent are reshaped to achieve robustly stable transportation. Parametric uncertainties and unmodeled dynamics of each agent are quantified and techniques from robust control theory are employed to choose the physical parameters of each agent to guarantee stability. Extensive simulation analysis and experimental results show that the proposed method guarantees stability in worst-case scenarios.