Rugged Environment Research Articles

A wind-solar energy harvester based on airflow enhancement mechanism for rail-side devices

A significant challenge arising from the rugged climate and environment is the provision of power to isolated railway-side equipment on the Plateau. Emerging renewable energy harvesting technologies present a promising solution. This paper proposes and confirms a Wind-Solar Energy Harvester (WSEH) founded on an Airflow Enhancement Mechanism (AFEM) for powering rail-side equipment. The proposed WSEH comprises of Vertical Axis Wind Turbine (VAWT), Flexible Photovoltaic Deflectors (FPVDs), and energy conversion and storage devices. The AFEM is executed founded on the FPVD that amplifies the airflow energy blown towards the VAWT due to the Blockage effect. The FPVD, grounded on an umbrella-like mechanism, unfolds as a PV panel for solar energy collection; and folds as a deflector to raise the wind energy collection potential for the VAWT. Through CFD simulation, the VAWT’s maximum power coefficient attains 0.387, and the optimum gain effect of FPVD is 66.54%. The prototypes, comprising VAWT and FPVDs, are scrutinized in a wind tunnel to authenticate the practicable effects illustrated by the no-load speed and load output of VAWT. The case study demonstrates that the WSEH creates 1566.82 kWh of electrical energy per year, sufficient for powering rail-side equipment on the Plateau.

A multifunctional integrated biomimetic spore nanoplatform for successively overcoming oral biological barriers

The biological barriers have seriously restricted the efficacious responses of oral delivery system in diseases treatment. Utilizing a carrier based on the single construction means is hard to overcome these obstacles simultaneously because the complex gastrointestinal tract environment requires carrier to have different or even contradictory properties. Interestingly, spore capsid (SC) integrates many unique biological characteristics, such as high resistance, good stability etc. This fact offers a boundless source of inspiration for the construction of multi-functional oral nanoplatform based on SC without further modification. Herein, we develop a type of biomimetic spore nanoplatform (SC@DS NPs) to successively overcome oral biological barriers. Firstly, doxorubicin (DOX) and sorafenib (SOR) are self-assembled to form carrier-free nanoparticles (DS NPs). Subsequently, SC is effectively separated from probiotic spores and served as a functional vehicle for delivering DS NPs. As expect, SC@DS NPs can efficaciously pass through the rugged stomach environment after oral administration and further be transported to the intestine. Surprisingly, we find that SC@DS NPs exhibit a significant improvement in the aspects of mucus penetration and transepithelial transport, which is related to the protein species of SC. This study demonstrates that SC@DS NPs can efficiently overcome multiple biological barriers and improve the therapeutic effect.

ANALYSIS OF RESOLVER TO DIGITAL CONVERTER FOR ANGULAR POSITION AND ROTATION OF STEPPER MOTOR

Electronic Monitoring, industrial motors, robots and vehicular power trains are necessary for higher efficiency, reliability, and safety, this technology provides the best angular position in terms of ruggedness, reliability, and resolution. Resolvers are developed mainly for military and aerospace applications. For high angular and velocity rotation of transformer, electronic control systems are necessary, which causes the noisy and rugged environment to avoid these, resolver to digital converter and op-amps are used. The resolver which is known as a rotary transformer converts the angular position of the shaft into Cartesian coordinates of components. The output of the transducer consists of two signals which are proportional to the sine and cosine of the angle which is represented in the form of a digital counterpart. Resolver to Digital Converter(RDC) driver is placed between microcontroller/ microprocessor and resolver, and to determine the angular position and rotation speed of the motor shaft, sine and cosine signals are used.

Bio-Inspired Take-Off Maneuver and Control in Vertical Jumping for Quadruped Robot with Manipulator.

The jumping motion of legged robots is an effective way to overcome obstacles in the rugged microgravity planetary exploration environment. At the same time, a quadruped robot with a manipulator can achieve operational tasks during movement, which is more practical. However, the additional manipulator will restrict the jumping ability of the quadruped robot due to the increase in the weight of the system, and more active degrees of freedom will increase the control complexity. To improve the jumping height of a quadruped robot with a manipulator, a bio-inspired take-off maneuver based on the coordination of upper and lower limbs is proposed in this paper. The kinetic energy and potential energy of the system are increased by driving the manipulator-end (ME) to swing upward, and the torso driven by the legs will delay reaching the required peak speed due to the additional load caused by the accelerated ME. When the acceleration of ME is less than zero, it will pull the body upward, which reduces the peak power of the leg joints. Therefore, the jumping ability of the system is improved. To realize continuous and stable jumping, a control framework based on whole-body control was established, in which the quadruped robot with a manipulator was a simplified floating seven-link model, and the hierarchical optimization was used to solve the target joint torques. This method greatly simplifies the dynamic model and is convenient for calculation. Finally, the jumping simulations in different gravity environments and a 15° slope were performed. The jump heights have all been improved after adding the arm swing, which verified the superiority of the bio-inspired take-off maneuver proposed in this paper. Furthermore, the stability of the jumping control method was testified by the continuous and stable jumping.

Adaptive and nonadaptive causes of heterogeneity in genetic differentiation across the Mimulus guttatus genome.

Genetic diversity becomes structured among populations over time due to genetic drift and divergent selection. Although population structure is often treated as a uniform underlying factor, recent resequencing studies of wild populations have demonstrated that diversity in many regions of the genome may be structured quite dissimilar to the genome-wide pattern. Here, we explored the adaptive and nonadaptive causes of such genomic heterogeneity using population-level, whole genome resequencing data obtained from annual Mimulus guttatus individuals collected across a rugged environment landscape. We found substantial variation in how genetic differentiation is structured both within and between chromosomes, although, in contrast to other studies, known inversion polymorphisms appear to serve only minor roles in this heterogeneity. In addition, much of the genome can be clustered into eight among-population genetic differentiation patterns, but only two of these clusters are particularly consistent with patterns of isolation by distance. By performing genotype-environment association analysis, we also identified genomic intervals where local adaptation to specific climate factors has accentuated genetic differentiation among populations, and candidate genes in these windows indicate climate adaptation may proceed through changes affecting specialized metabolism, drought resistance, and development. Finally, by integrating our findings with previous studies, we show that multiple aspects of plant reproductive biology may be common targets of balancing selection and that variants historically involved in climate adaptation among populations have probably also fuelled rapid adaptation to microgeographic environmental variation within sites.

Thiti as an Institution for Sustainable Management of the Resources in the Himalaya

Himalayan communities still have traditional ecological knowledge with a strong social mechanism for the management of resources to live in a harsh environment. This paper mainly discusses two thematic issues; how the Himalayan people optimize the use of limited resources to thrive in a harsh environment, and what the key socio-cultural factors which help them to survive in the rugged environment sustainably. The paper is based on nine months of ethnographic study from 2012-2018among Gurungs, agro-pastoral communities in Nhason Valley of Manang. The findings reveal that thiti is a socio-cultural institution to Himalayan dwellers that controls the behavior of the people in a society; the source of the awareness and recognition of the fragile resources for living in rugged terrain; means of defining rights on resources. In the Himalayan region, indigenous ecological knowledge does not work in isolation; it is intertwined with a socio-cultural institution that unfolds in a social context.

A Cross-Platform Web3D Monitoring System of the Three-Machine Equipment in a Fully Mechanized Coalface Based on the Skeleton Model and Sensor Data

A fully mechanized coalface is a rugged environment that has poor visibility. The traditional video monitoring system has problems such as a lack of realism, a blurry monitoring effect, and poor reliability. It is an important task to monitor the operations of the three-machine equipment (we will refer to the shearer, hydraulic support, and scraper conveyor as the three-machine equipment) intuitively, accurately, and timely and ensure that it is operating safely. This study proposed a cross-platform Web3D monitoring system for the three-machine equipment. First, the virtual mesh model and skeleton model that was embedded in the mesh model were established according to three-machine ontology and basic motion units. Second, the kinematic model of the three-machine skeleton was established via the inverse kinematic modeling of the hydraulic support and the coordinate calculation of the vertices on the three-machine skeleton. Third, the motion data, which were captured by sensors, were applied to drive the movement of the three-machine skeleton and mesh model. Finally, WebGL, which is the latest Internet graphics standard, was used to render the three-machine models, and the performance of this monitoring system is tested on different equipment in the laboratory. The results of the test show that the three-machine cross-platform monitoring system has splendid performance, and it realizes cross-platform 3D monitoring effectively in the laboratory. In the future, this system will be used as a supervisory tool and be integrated with the traditional monitoring system to monitor the three-machine equipment with the field staff.

Design and fabrication of foldable electric bicycle

Sustainable and flexible modes of transportation are gaining popularity these days, primarily due to their economic and environmental benefits. It has changed the prime focus of automakers towards electric vehicles. Today, cycling has become a common mode of short-distance travel, mainly due to its health benefits and flexibility. But they are not easy to carry around. Thus, incorporating a folding mechanism to the current design can improve its portability. Also, the integration of an electrical motor further enhances the cycling experience in a rugged environment. This paper describes the process of design, development, and fabrication of a foldable electric bicycle from an ordinary bicycle. The process of designing and fabrication involves the design and manufacture of folding and locking mechanisms. The fabricated model is tested under various terrains and loads. Similarly, the BLDC motor is tested under different conditions, recording motor characteristics. It was found that bicycle conversion is much more feasible than fabricating the whole cycle.

How does co-registration affect geomorphic change estimates in multi-temporal surveys?

ABSTRACT High-Resolution Topography (HRT) data sets are becoming increasingly available, improving our ability and opportunities to monitor geomorphic changes through multi-temporal Digital Terrain Models (DTMs). The use of repeated topographic surveys enables inferring the sediment dynamics of hazardous geomorphic processes such as floods, debris flows, and landslides, and allows us to derive important information on the risks often associated with these processes. The topographic surveying platforms, georeferencing systems, and processing tools have seen important developments in the last two decades, in particular Light Detection And Ranging (LiDAR) technology used in Airborne Laser Scanning (ALS) and Terrestrial Laser Scanning (TLS). Moreover, HRT data, produced through these techniques, changed a lot in terms of point cloud density, accuracy and precision over time. Therefore, old “legacy” data sets and recent surveys can often show comparison problems, especially when multi-temporal data are not homogeneous in terms of quality and uncertainties. In this context, data co-registration should be used to guarantee the coherence among multi-temporal surveys, minimizing, on stable areas, the distance between corresponding points acquired at different epochs. Although several studies highlight that this process is fundamental to properly compare multi-temporal DTMs, it is often not addressed in LiDAR post-processing workflows. In this paper we focus on the alignment of multi-temporal surveys in a topographically complex and rugged environment as the Moscardo debris-flow catchment (Eastern Italian Alps), testing various co-registration methods to align multi-temporal ALS point clouds (i.e. years 2003, 2009 and 2013) and the derived DTMs. In particular, we tested the pairwise registration with manual correspondences, the Iterative Closest Point (ICP) algorithm and a mathematical model that allows aligning simultaneously a generic number of point clouds, the so-called Generalized Procrustes Analysis (GPA), also in its GPA-ICP variant. Then, to correct the possible small inaccuracies generated from the gridding interpolation process, a custom-developed DTM co-registration tool (GRD-CoReg) was used to align gridded data. Both alignment phases (i.e. at point cloud and DTM level) proved to be fundamental and allowed us to obtain proper and reliable DTMs of Difference (DoDs), useful to quantify the debris mobilized and to detect the spatial and temporal patterns of catchment-scale erosion and deposition. The consistency of DoDs data was verified through the comparison between the erosion estimate of DoDs and the volumes of debris-flow events measured by the monitoring station close to the Moscardo torrent catchment outlet. The GPA-ICP algorithm followed by the GRD-CoReg tool proved to be the most effective solution for improving DoDs results with a decrease of systematic trend due to vertical and horizontal uncertainties between surveys, especially at steep slopes. The net volume difference (i.e. the sediment output from the catchment) of the 2003–2013 period changed from 3,237,896 m3 to 135,902 m3 in DoDs obtained from not co-registered and co-registered DTMs. The volume of debris flows measured at the catchment outlet during the same time interval amounts to 169,660 m3. The comparison with debris-flow volume measures at the monitoring station shows, therefore, that the DTMs obtained from the co-registration processes generate more reliable DoDs than those obtained from the raw DTMs (without the alignment).

Inferences on Sicilian Mesolithic subsistence patterns from cross-sectional geometry and entheseal changes

Using cross-sectional geometry (CSG), entheseal changes (ECs), and presence of external auditory meatus exostosis (EAE), this study tests the hypothesis—based on isotopic and zooarchaeological evidence—that in the Sicilian Mesolithic terrestrial rather than marine resources were predominantly exploited, in substantial continuity with previous Epigravettian hunters. Results show similarities in the general frequency of ECs—a rough proxy for overall activity—with Late Pleistocene hunters, in contrast with Mesolithic coastal foragers or Neolithic herders/farmers. Yet, CSG suggests that this possible continuity in the type of resources exploited was accompanied by a behavioral change, and in particular the abandonment of the throwing technology, possibly in favor of new tools such as traps and the bow and arrow. In fact, the dramatic decrease in humeral bilateral asymmetry documented at a European level with the Pleistocene-Holocene transition can be found also in the Sicilian Mesolithic. Results for the lower limb appear compatible with a certain degree of terrestrial mobility in a rugged environment. The frequency of EAE suggests that activities related to water were present but not common; however, their prominence is difficult to determine given the small sample size. The pattern of information provided by the proxies for activity used here is complex and partially contrasting, but has the potential to integrate and enrich archeological methods and biochemical approaches. This study corroborates a varied scenario of continuity and discontinuity in subsistence at the Pleistocene-Holocene transition, and highlights the importance of a regional bioarchaeological approach of human biological and behavioral adaptations.

Remaining useful life (RUL) estimation of electronic solder joints in rugged environment under random vibration

The remaining useful life (RUL) of electronic modules under the influence of rugged random-vibration and operational conditions is investigated in this paper. The effects of storage conditions and soft failures, caused by the vibrations to solder joints of a printed circuit board (PCB) are analyzed. The RUL is estimated with the help of vibration testing and finite element analysis techniques. Keeping in view the standard and working environmental conditions, the PCB of a power distribution module is subjected to random and sine vibrations. Besides the significance of fatigue damage and RUL estimation of solder joints, caused by storage or operation for a period of five years has not been addressed in existing literature so far. The current study performs the modal analysis to find the natural frequencies, mode shapes, and participation factor ratios of a PCB and its components. These natural frequencies are subsequently verified via comparison with experimental sine sweep results. A random vibration test over the frequency range from 10 Hz to 2000 Hz is also applied for recording the time-to-failure ratio of the PCB. Moreover, the spectrum analysis is performed using the commercial ANSYS software, to assess the acceleration response and the stress power spectral density (PSD) of the critical solder joints. The stress PSD is then used to estimate the random vibration fatigue damage of the solder joint. The calculated fatigue life, based on the modified Miner's rule and the Basquin power-law conform to the actual random vibration testing results.

A Probiotic Spore‐Based Oral Autonomous Nanoparticles Generator for Cancer Therapy

Spores, the dormant life forms of probiotics, can germinate to metabolically active vegetative cells with the disintegration of their hydrophobic protein coat in the intestinal microenvironment, which provides the possibility for the formation of nanoparticles (NPs) in vivo. Inspired by the natural physiological process of spores, herein, an oral autonomous NPs generator is developed to overcome the spatially variable gastrointestinal tract environment and multibiological barriers. Spores modified with deoxycholic acid (DA) and loaded with chemotherapeutic drugs (doxorubicin and sorafenib, DOX/SOR) serve as an autonomous production line of NPs, which can efficaciously protect the drugs passing through the rugged environment of the stomach and furthermore can be transported to the intestinal environment and colonized rapidly. Subsequently, the DOX/SOR/Spore-DA NPs are produced by the autonomous NPs generator in the intestinal regions based on the disintegrated hydrophobic protein and the hydrophilic DA, and they can efficiently penetrate the epithelial cells via the bile acid pathway, increasing basolateral drug release. In vitro and in vivo studies confirm that this biological nanogenerator can autonomously produce substantial NPs in the intestine, providing a promising strategy for cancer therapy.

Development and characterization of a multilayer silver/silver-tantalum oxide thin film coating on stainless steel for biomedical applications

Stainless steel 316L (SS 316L) is widely used in biomedical applications, particularly in surgical tools. Although this class of material has good wear and mechanical properties, it still lacks in antibacterial properties. Therefore, various surface modifications such as antibacterial coatings have been developed to enhance its properties. In this study, the surface of SS 316L was engineered with a thin multi-layer of tantalum oxide (TaO) and silver (Ag) with thickness of 4.7–6.4 μm. The thin film multilayered coatings were deposited using physical vapor deposition (PVD) magnetron sputtering. In this study, Ag/AgTa2O5 nanocomposite thin film is developed to avoid or limit bacterial adhesion on surgical tool surfaces. The as-deposited Ag/AgTa2O5 nanocomposite film were thermally treated to enhance the mechanical properties of the film. The thermal annealing of the as-sputtered thin film at 400 °C induced segregated Ag microstructure, increased the crystallinity and adhesion strength by about 152% (2916 ± 147 mN). The 400 °C annealed thin film exhibited hydrophobicity (102.5°) and thermal stability properties. The superior adhesion strength of the thermally treated film reduces and slows down delamination while in use at the rugged surgical environment.

Deterministic Modeling of 5G Millimeter-Wave Communication in an Underground Mine Tunnel

This paper presents broadband simulations and measurements of Millimeter-Waves (mm-wave) propagation in a rugged underground mine environment. Mathematical formulation was carried out in the framework of Uniform Theory of Diffraction (UTD) to develop a deterministic Ray-Tracing (RT) model under Line-Of-Sight (LOS) condition. The developed theoretical model was then validated experimentally in Frequency Domain (FD) and Time Domain (TD). A significant agreement between simulations and measurements is achieved in both domains. The rough surfaces of the mine are modeled deterministically as groups of diffracting wedges having random dimensions (heights, angles) being transversely oriented throughout the gallery. Acute (inferior to 30°) and obtuse (superior to 120°) wedges angles are found to have significant effects on the overall propagation performance. In the mm-wave band, the UTD diffraction phenomenon is evident and must be considered in the design of underground mine channels. In fact, the presented model is found to be capable of predicting the complex multipath of underground mine channels, due to the ray-optical behavior at mm-wave bands.

Diversity in ancient Maya water management strategies and landscapes at Caracol, Belize, and Tikal, Guatemala

The Classic Period Maya cities of Caracol and Tikal possessed unique urban morphologies of water management. In part, the built environment at each city reflects adaptations to the hydrology of their landscapes. Caracol exists in a rugged, hilly, and karst environment; its residents invested their landesque capital in constructing agricultural terraces and residential reservoirs. These features created Caracol's anthropogenic garden‐city landscape. This landscape was unified through a dendritic causeway system and the distributed nature of monumental nodes. The landscape of Tikal exhibits a lower slope, is generally smoother, and its residents invested in constructing a large and condensed site core along with their monumental reservoirs. Additionally, the people of Tikal invested in bajo margin agriculture. The differences in urban form and hydrology conditioned the resulting water management strategies employed by both cities; the resulting built environmental features are preserved in the archeological record. Because of its higher slopes, Caracol's landscape presents a greater hazard for soil erosion and faster rainfall runoff. Yet, the construction of distributed residential reservoirs and agricultural terraces acted to collect rainfall, increase soil saturation, and reduce this runoff. Tikal's landscape on the whole presents fewer hazards in terms of soil erosion but perhaps greater issues from torrential rainfall. Water management infrastructure at both cities reflects both their unique urban morphologies and environmental conditions.This article is categorized under: Engineering Water > Planning Water Science of Water > Water and Environmental Change

Spatiotemporal characteristics and temporal stability of soil water in an alpine meadow on the northern Tibetan Plateau

The spatiotemporal characteristics of soil water content (SWC) have a significant influence on vegetation degradation and growth in alpine meadow ecosystems. The spatiotemporal variability and temporal stability (TS) of SWC, however, have rarely been studied on the northern Tibetan Plateau owing to the rugged and hostile sampling environment. The objective of this study was to analyze the spatiotemporal variability and the TS of SWC in various layers of the soil, to a depth of 50 cm in a 33.5 hm2 plot, with the data obtained from 113 measuring locations collected on 22 sampling occasions during the growing seasons of 2015 and 2016. The SWC was moderately variable both in time (two consecutive growing seasons) and horizontal space (plot). The variabilities, however, did not vary consistently with increasing depth for the various dominant influencing factors. The SWC in the undeveloped, shallow, and stony alpine meadow soil was temporally stable; TS did not depend on depth due to disturbances by grass roots...

Color Constancy of Rare-Earth Solution Image with Adaptive Parameter

It is known that the color of the rare earth solution image varies with the illumination condition due to the rugged environment of rare earth extraction industry and attenuation of lights, which makes soft-sensing model for rare earth element content based on the color characteristics of the rare earth solution have larger error. An unsupervised color correction algorithm with adaptive optimization of parameters for rare earth solution is proposed in this paper. Such an algorithm can realize proper color correction of rare earth solution by using Genetic Algorithm (GA) based Grey Edge algorithm. The GA based Grey Edge algorithm can handle the issue of parameter adaptive optimization caused by the rare earth solution change with the different illumination and extraction tank, and reduce the error between the designated area of the image and the designated area of the standard image. The simulation shows the effectiveness of the proposed algorithm.

Android App Controlled Bluetooth Robotic Vehicle

The objective of the present work is to design and develop an android app based user interface to control a robotic vehicle using wireless bluetooth technology. The entire system consists of carefully selected replaceable low-cost components to meet the rugged industrial environment. The proposed single-board in-vehicle embedded system is equipped with the HC-05 bluetooth model to interact with microcontroller and android app, dc gear motor and L293D motor driver to control the kinetics of a robotic vehicle, and ATmega328P microcontroller as core processing unit fixed on self-designed chassis. The back-hand design for the android app is developed using open source called ‘App Inventor’ developed by MIT and suitable to develop app without Java platform. The in-vehicle electronics hardware is developed around the ATmega328P microcontroller and bluetooth module is interfaced with microcontroller through the UART protocol to exchange the data with android app. By pressing remote button developed in the android app the direction of the robotic vehicle can be decided. The major advantages of this proposed design is, minimum version of in-built bluetooth smartphone is used to install the developed app and wireless bluetooth technology offers zero communication cost. Moreover, this robotic vehicle can also be utilized other application such as, exploring the toxic area, detection of explosive landmines, multipurpose surveillance vehicle.

Declines in the mammal assemblage of a rugged sandstone environment in Kakadu National Park, Northern Territory, Australia

There has been marked recent decline in the terrestrial mammal fauna across much of northern Australia, with most documentation of such decline for lowland areas. Here we report changes in the assemblage of small mammals in a rugged sandstone environment (Nawurlandja, in Kakadu National Park) over intermittent sampling between 1977 and 2002. Four native mammal species were commonly recorded in the original sampling: sandstone antechinus (Pseudantechinus bilarni), northern quoll (Dasyurus hallucatus), Arnhem rock-rat (Zyzomys maini) and common rock-rat (Z. argurus). Trap success rates declined significantly for the northern quoll, Arnhem rock-rat and all species combined, but increased for the common rock-rat. Despite being recorded commonly in the initial (1977–79) study, no Arnhem rock-rats were recorded in the most recent (2002) sampling. Trap success rates for northern quoll declined by ~90% from 1977–79 to 2002. The reasons for change are not clear-cut. Notably, all sampling occurred before the arrival of cane toads (Rhinella marina), a factor that has caused severe decline in northern quoll numbers elsewhere. Fire was more frequent in the sampling area in the period preceding the 2002 sampling than it was in the period preceding the initial (1977–79) sampling, and this may have contributed to change in mammal abundance.

All-metal flexible large-area multiband waveplate.

We propose and demonstrate an all-metal flexible reflective multiband waveplate based on nano-grating structure using high efficient electroplating growing process, which exhibits quarter waveplate at two wavelengths (λ = 465nm and λ = 921nm) and half waveplate at another wavelength (λ = 656nm). Using Finite Difference Time Domain (FDTD) modeling, the phase shift and reflection efficiency are simulated and designed for a variety of geometrical parameters. A fast and cost-effective technique based on conventional interference lithography and nickel electroplating process is demonstrated to fabricate the all-metal, large-area and flexible waveplate. Experimental results show that the fabricated monolithic all-metal nano structure of the proposed device are in high fidelity with the structure on template and the optical performance of the device are in excellent agreement with the theoretical prediction. The proposed structure and the fabrication method suggests an effective way to realize all-metal, ultrathin, self-supporting and flexible devices for various applications in rugged environment such as high temperature or high pressure environment, and also in the fast growing fields of flexible (wearable) optoelectronics, flexible displays and other curved or nonplanar devices.