Ground Forces Research Articles

Correlations between the EMG Structure of Movement Patterns and Activity of Postural Muscles in Able-Bodied and Wheelchair Fencers.

The study involved Paralympic wheelchair fencers (N = 7) in two disability categories, and able-bodied female epee fencers (N = 7), members of the polish paralympic fencing teams. The performance of postural muscles and sword arm muscles in both groups of fencers, and of the front and rear leg muscles in the able-bodied fencers, was examined using surface electromyography with an accelerometer and the OptiTrack motion analysis system, as well as ground force reaction platforms. The activation sequence of individual muscles was determined and the structure of movement patterns in able-bodied and wheelchair fencers was formulated. A statistically significant correlation was found between the complex motor reaction time and latissimus dorsi muscle activation (p = 0.039, Z = -2.062) in wheelchair fencers. High correlations between the vertical force and EMG signal values of the gastrocnemius caput laterale muscle (0.85 for p = 0.022) were found in able-bodied fencers. A heuristic analysis indicated the significance of postural muscles in the movement patterns of wheelchair and able-bodied fencers. These muscles play a crucial role in the anticipatory postural adjustment of the trunk during technical fencing actions, including attacks on the opponent's body.

Study of properties of real vibroseis signals contaminated by harmonic noise

Properties of the ground force signal complicated by harmonics are studied. It is shown that the adaptation filters, that enable matching the amplitude- and phase- frequency characteristics of harmonics in the corresponding frequency range, have a simple form. The problem of focusing a signal containing harmonics using correlation and deconvolution is discussed. An example of using harmonics to expand the signal spectrum is given.

FINITE ELEMENT ANALYSIS OF A KNEE JOINT DURING JUMP

Athletes experience high levels of stress during sports activities. One of the most common activities is jumping. This is a very complex activity, which can lead to injuries and long recovery periods. In this research, professional athletes performed jumps in order to obtain ground force values from a force plate. A combination of ground force measurement and inverse dynamics was used to obtain knee joint force values during jumping. The obtained values were then used for the finite element analysis of a knee joint model in order to calculate stress values in the knee joint, with focus on femoral cartilage and menisci. The highest stress values were obtained at the anterior and posterior horn of the medial meniscus, with the highest stress value of 4.894 MPa. Femoral cartilage had lower value, with the maximum stress of 0.391 MPa.

Using input-output tables to set goals

Within the framework of the presented article, the authors consider the issue related to the construction and use of input-output tables necessary to determine the main goals. In particular, the input-output model is considered, which reveals in detail the links between different sectors of production in the economy, due to which, with a detailed analysis, it is possible to compile a number of tables that fully show the country's production by industry. The authors focus on the fact that this model can be effectively used by the ground artillery of the ground forces of the Russian Federation in drawing up a diagram that can show both the rear communications of the enemy and all of its production, which is somehow used for military purposes. In addition, the authors note that this model is based on the general economic equilibrium model, which, in turn, allows not only to study the relationship in the economy and determine the intersectoral balance, but also to detect weak points in the economy. The article emphasizes the need to apply the input-output model in the military industry, since today, due to the aggravation of the geopolitical conflict, the supply of the military-industrial complex is vital for any army, and often the effectiveness of the supply determined the outcome of battles or the preparation of turning points in wars. The article presents a number of tables and formulas that reflect the calculations and assessment of the costs of different groups of troops, which emphasizes the universality of the model under consideration. The final part of the article is devoted to highlighting the factors that must be taken into account in the management of artillery units and in order to achieve their goals.

The Role of Armed Non-State Actors in Iran’s Syria Strategy: A Case Study of Fatemiyoun and Zainabiyoun Brigades

ABSTRACT Over the past two decades, there has been a growing tendency among Middle Eastern states to use armed non-state actors (ANSAs) as proxies, making them a constant feature of regional conflicts. Fatemiyoun and Zainabiyoun brigades are two recent examples of state-sponsored ANSAs, which have played a significant role as Iran’s proxies in the course of the Syrian conflict. This article seeks to answer the question as to what role the Fatemiyoun and Zainabiyoun brigades have played in Iran’s military strategy in Syria and how effective they have been in securing Tehran’s strategic interests in the war-torn country. The article argues that following the outbreak of the Syrian crisis—as the most critical challenge to Iran’s foreign policy in the Middle East over the past decade—and due to Iran’s restraints in sustaining a large-scale direct military presence in Syria, the two Afghan and Pakistani brigades acted as Iran’s ground forces, reducing human and financial costs of a direct military engagement for Tehran. The effective role played by the two brigades was mainly reflected in the four strategic battles of Aleppo, Southern Syria, Palmyra, and Eastern Syria.

Management of the ground force reserve components in development of defense posture to face threats in West Kalimantan Province

West Kalimantan Province geographically is part of Indonesia which borders directly with neighboring countries with potential hybrid threats and non-military threats. Based on the Law of the Republic of Indonesia Number 3 of 2002 concerning National Defense explained that the defense of Indonesia organized with a universal defense system to face any form of threat. Indonesian defense posture relying on the Indonesian National Army as the main component who are ready to face the threat. In accordance with the mandate of the Republic of Indonesia Law Number 23 of 2019 concerning Management of National Resources, in addition to relying on the strength and capabilities of the Indonesian National Army, also involves reserve components who have received basic military training to increase the strength of the main components in a short time. This study aims to analyze the management, constraints and efforts made in management of the ground force reserve component in the development of a defense posture to deal with threats in West Kalimantan Province. The method used in this research is qualitative method with primary data collection techniques that is interviews with resource persons and secondary data in the form of literature studies. Results research shows that management of the ground force reserve component implemented by territorial command through the management functions of planning, organizing, actuating and controlling. The obstacles faced are geographical factors, budget constraints, central and local governments and companies do not understand the regulations, limited educators, trainers and infrastructure, limited communication tools to control the members of the ground force reserve component. As for efforts to overcome obstacles in management of the ground force reserve component in West Kalimantan Province is to optimize the implementation of socialization, intensify budget coordination, increase the quantity and quality of human resources and improve facilities and coaching programs.

Improving Surface Wind Speed Forecasts Using an Offline Surface Multilayer Model With Optimal Ground Forcing

AbstractAn essential task of numerical weather prediction (NWP) is accurate surface wind speed prediction. However, current NWP models contain significant systematic errors due in part to indeterminate ground forcing (GF). This study considers an optimal virtual GF (GFo) derived by training observed and simulated data sets of 10‐m wind speeds (WS10) for summer and winter. The GFo is added to an offline surface multilayer model (SMM) to revise predictions of WS10 in China by the Weather Research and Forecasting model (WRF). This revision is a data‐based optimization under physical constraints. It reduces WS10 errors and offers wide applicability. The resulting model outperforms two purely physical forecasts (the original WRF forecast and the SMM with physical GF parameterized using urban, vegetation, and subgrid topography) and two purely data‐based revisions (i.e., multilinear regression and multilayer perceptron). Compared with the original WRF forecasting, using the GFo scheme reduces the root mean square error in WS10 across China by 25% in summer and 32% in winter. The frontal area index of GFo indicates that it includes both the effects of indeterminate GF and other possible complex physical processes associated with WS10.

Smart Lacelock: A Novel Shoelace Tensioning Device for Human Motion Sensing

Shoe-mounted wearable sensors may serve a variety of important purposes (activity recognition, energy expenditure estimation, and so on) by providing rich information about human locomotion. However, reliably attaching such sensors to shoes still remains a challenge. Furthermore, pressure-sensing elements in such shoe sensor systems often suffer from poor durability due to the large dynamic load. This work presents a novel shoe-mounted sensor named Smart Lacelock, which takes the form of a common shoelace tensioning device (shoelace lock). With its unique form factor, the Smart Lacelock can be securely attached to the top of a shoe with minimal effort, enabling its embedded inertia measurement unit (IMU) to provide reliable 3-D motion measurement of the foot. Furthermore, the Smart Lacelock incorporates a load cell to measure the force applied by the shoelace, providing valuable information related to ankle movement, foot/shoe shape change, and ground force. Design details of the device are presented, including the mechanical structure and electronic circuitry. We also conducted a ten-participant human study, in which signals were recorded during free ankle swing, body weight (BW) shifting, sit-to-stand (STS), and overground walking. The results demonstrated the Smart Lacelock’s capability of providing consistent and observable responses to single contributing factors (ankle movement and foot loading) as well as complex movements with clearly defined events of interest (STS and walking). Such unique capability suggests that the Smart Lacelock may serve as an important source of human movement information to support related applications such as activity recognition and gait event detection.

Detecting Gait Events from Accelerations Using Reservoir Computing.

Segmenting the gait cycle into multiple phases using gait event detection (GED) is a well-researched subject with many accurate algorithms. However, the algorithms that are able to perform accurate and robust GED for real-life environments and physical diseases tend to be too complex for their implementation on simple hardware systems limited in computing power and memory, such as those used in wearable devices. This study focuses on a numerical implementation of a reservoir computing (RC) algorithm called the echo state network (ESN) that is based on simple computational steps that are easy to implement on portable hardware systems for real-time detection. RC is a neural network method that is widely used for signal processing applications and uses a fast-training method based on a ridge regression adapted to the large quantity and variety of IMU data needed to use RC in various real-life environment GED. In this study, an ESN was used to perform offline GED with gait data from IMU and ground force sensors retrieved from three databases for a total of 28 healthy adults and 15 walking conditions. Our main finding is that despite its low complexity, ESN is robust for GED, with performance comparable to other state-of-the-art algorithms. Our results show the ESN is robust enough to obtain good detection results in all conditions if the algorithm is trained with variable data that match those conditions. The distribution of the mean absolute errors (MAE) between the detection times from the ESN and the force sensors were between 40 and 120 ms for 6 defined gait events (95th percentile). We compared our ESN with four different state-of-the-art algorithms from the literature. The ESN obtained a MAE not more than 10 ms above three other reference algorithms for normal walking indoor and outdoor conditions and yielded the 2nd lowest MAE and the 2nd highest true positive rate and specificity when applied to outdoor walking and running conditions. Our work opens the door to using the ESN as a GED for applications in wearable sensors for long-term patient monitoring.

Deep Reinforcement Learning for Autonomous Dynamic Skid Steer Vehicle Trajectory Tracking

Designing controllers for skid-steered wheeled robots is complex due to the interaction of the tires with the ground and wheel slip due to the skid-steer driving mechanism, leading to nonlinear dynamics. Due to the recent success of reinforcement learning algorithms for mobile robot control, the Deep Deterministic Policy Gradients (DDPG) was successfully implemented and an algorithm was designed for continuous control problems. The complex dynamics of the vehicle model were dealt with and the advantages of deep neural networks were leveraged for their generalizability. Reinforcement learning was used to gather information and train the agent in an unsupervised manner. The performance of the trained policy on the six degrees of freedom dynamic model simulation was demonstrated with ground force interactions. The system met the requirement to stay within the distance of half the vehicle width from reference paths.

Analyses Of Physical Performance Determinants In Male Professional Soccer Players

Aerobic, anaerobic and anthropometric characteristics have been reported as important components of physical performance (PP) in soccer. It is theorized that better PP can enhance the degree of success and reduce risk of musculoskeletal injuries. However, evidence of how PP of each player impacts soccer team’s success is lacking, especially at the professional level. PURPOSE: To determine the effect of individual players PP on team performance success in male professional soccer league. METHODS: Cross-sectional study design with 114 male professional soccer players of the highest Czech league were classified according to team´s final league ranking into four groups: (G1) 1st-4th ranking (n = 31), (G2) 5th-8th ranking (n = 32), (G3) 9th-12th (n = 26) and (G4) 13th-16th (n = 25). PP determinants were assessed using the following indicators: Body height (BH), body weight (BW), fat mass (FM), height of vertical jump (CMJ), maximal vertical ground force (VGF), isokinetic strength (60°.s-1) of knee extensors (KE), flexors (KF) for dominant (DL) and non-dominant (NL) leg and maximal oxygen uptake (VO2max). Multivariate analyses of variances, Bonferroni post hoc test, and partial eta square (ηp2) were used for statistical assessment. RESULTS: A significant overall effect of PP on team’s performance success (p < 0.01, ηp2 = 0.16) was found. Post-hoc analyses revealed players in the G1 had significantly (p < 0.05) higher CMJ (43.70 ± 5.09 cm) compared to G3 (38.60 ± 3.98 cm) and G4 (40.40 ± 3.51 cm) players. Moreover, players in the G1 generated greater VGF (26.93 ± 2.80 N.kg-1) compare to G4 (25.14 ± 1.79 N.kg-1) and higher values of KE compare to G3 players in both DL and NL (G1: KEDL = 3.19 ± 0.47 N.m.kg-1, KENL = 3.17 ± 0.46 N.m.kg-1, G3: KEDL = 2.89 ± 0.31 N.m.kg-1, KENL = 2.87 ± 0.28 N.m.kg-1). Players in the most successful teams (G1) also showed significantly higher VO2max (60.32 ± 2.62 ml.min.kg-1) compare to players in the lowest group (G4: 57.87 ± 2.74 ml.min.kg-1). CONCLUSIONS: The current findings indicate PP including CMJ, VGF, muscle strength of KEs and VO2max of individual player is associated with final team ranks in the Czech professional soccer league. This evidence may be valuable to discuss team’s success in male professional soccer league.

Rotational Stability of the Knee in a Comparative Study of Anterior Cruciate Ligament Reconstruction Using the Double-Bundle and Single-Bundle Techniques.

The purpsose of this study was to evaluate the biomechanical outcomes of patients who underwent ACL reconstruction either with the DB or SB technique. We hypothesized that the DB technique would provide better rotation control of the knee following ACL reconstruction. The study included seventy-five participants (26 DB, 22 SB, and 27 healthy volunteers). Only cases with at least one year of postoperative follow-up were included. The participants performed three different demand tasks: walk task, walk and change direction, and stair descent and change direction, which was tracked using a three-dimensional 4-camera optoelectronic system. The following kinematic data were analyzed: tibial rotation amplitude and maximal internal and external rotation. Knees with ACL reconstruction were compared to contralateral knees with intact ACL and healthy knees. Clinical outcomes were determined using the subjective and objective International Knee Documentation Committee (IKDC) questionnaire and a manual arthrometer (KT 1000). Both surgical groups exhibited similar clinical outcomes (mean subjective IKDC 91 SB vs. 90 DB, P=0.815; KT 1000 difference: 2mm in both groups, P=0.772). The vertical component of the ground force reaction revealed no differences between the surgical and control groups (P>0.05). Tibial rotation amplitude and maximal internal and external rotation were similar between the control, SB, and DB groups in all three different demand tasks (P>0.05). ACL reconstruction using either the SB or DB technique can restore rotational control to the level of a healthy knee. No clinical or functional differences were found between the SB and DB surgical options.

Effects and global sensitivity analysis of vibrator-ground coupling parameters on ground force under excitation of sweep frequency

Ground force is the key index to evaluate the output of the seismic vibrator. To generate desired ground force, the relationship between coupling parameters and ground force should be investigated. In this paper, a method for calculating ground force is proposed based on half-space theory, and its validity is carried out by field test. According to the analysis of coupling parameters, the baseplate’s mass, the mass of reaction-mass, the baseplate area, the soil elastic modulus, and the soil density are determined to be analyzed. The ground forces under the changes of coupling parameters are studied. Results show that each parameter has a different contribution to affecting the ground force at different frequencies. The heavier reaction mass is beneficial for greater vibration output below 20 Hz. Smaller baseplate mass, bigger baseplate area, and higher soil density are helpful to increase ground force in the band of 20–50 Hz. In addition, higher soil elastic modulus brings greater ground force beyond 50 Hz. Then global sensitivity analysis for ground force is investigated with Sobol’s method. It indicates that the ground force is dominated by the reaction mass at low frequencies. With significant interactions, the soil elastic modulus has a great effect on the ground force at high frequencies, followed by the baseplate’s mass, baseplate area, and soil density.

Predictive Simulations of Human Sprinting: Effects of Muscle-Tendon Properties on Sprint Performance.

We combined a full-body musculoskeletal model with dynamic optimization theory to predict the biomechanics of maximum-speed sprinting and evaluate the effects of changes in muscle-tendon properties on sprint performance. The body was modeled as a three-dimensional skeleton actuated by 86 muscle-tendon units. A simulation of jogging was used as an initial guess to generate a predictive dynamic optimization solution for maximum-speed sprinting. Nominal values of lower-limb muscle strength, muscle fascicle length, muscle intrinsic maximum shortening velocity (fiber-type composition), and tendon compliance were then altered incrementally to study the relative influence of each property on sprint performance. Model-predicted patterns of full-body motion, ground forces, and muscle activations were in general agreement with experimental data recorded for maximum-effort sprinting. Maximum sprinting speed was 1.3 times more sensitive to a change in muscle strength compared with the same change in muscle fascicle length, 2.0 times more sensitive to a change in muscle fascicle length compared with the same change in muscle intrinsic maximum shortening velocity, and 9.1 times more sensitive to a change in muscle intrinsic maximum shortening velocity compared with the same change in tendon compliance. A 10% increase in muscle strength increased maximum sprinting speed by 5.9%, whereas increasing muscle fascicle length, muscle intrinsic maximum shortening velocity, and tendon compliance by 10% increased maximum sprinting speed by 4.7%, 2.4%, and 0.3%, respectively. Sprint performance was most sensitive to changes in muscle strength and least affected by changes in tendon compliance. Sprint performance was also more heavily influenced by changes in muscle fascicle length than muscle intrinsic maximum shortening velocity. These results could inform training methods aimed at optimizing performance in elite sprinters.

Effects of Walking With a Cane on Frontal Plane Hip Joint Loading in Patients With Late-Stage Unilateral Hip Osteoarthritis

ObjectiveTo investigate the effects of walking with a cane on frontal plain bilateral hip joint loading in patients with late-stage unilateral hip osteoarthritis (OA). DesignNonrandomized experimental design. SettingUrban inpatient hospital. ParticipantsAdults (men, n=10; women, n=17) with osteoarthritis who were scheduled for total hip arthroplasty (N=27). InterventionGait with and without a T-cane was assessed using a 3-dimensional motion analysis system. Main Outcome MeasuresPeak hip adduction moment and hip adduction moment impulse, vertical ground reaction force, and ground reaction force impulse were assessed under 4 different conditions: OA side vs non-OA side with non-cane gait, OA side vs non-OA side with cane gait, non-cane vs cane gait on OA side, and non-cane vs cane gait on non-OA side. The lateral trunk lean angle in the stance phase on both sides was compared between with and without a cane. Pain during walking with and without a cane was also determined using a visual analog scale (0=no pain; 100=most painful). ResultsWalking with a cane reduced the peak hip adduction moment from an average of 0.76 to 0.57 Nm/kg (reduction approximately 25%) and the mean hip adduction moment impulse from 50.58 to 42.78 Nm/kg (reduction approximately 15%) on the affected side. Walking with a cane reduced the peak ground reaction force from an average of 10.15 to 9.20 N/kg but did not markedly affect the mean ground reaction force impulse on the affected side. The mean impulse of vertical ground force and hip adduction moment on the nonaffected side with a T-cane was larger than that without a cane (940.4 vs 899.2, 73.7 vs 68.8, respectively), albeit without statistical significance. The mean lateral trunk lean angle on the affected side was 5.85±3.95 degrees with a non-cane gait and 4.46±2.66 degrees with a T-cane gait, showing a significant difference. Furthermore, walking with a cane was associated with a significant decrease in the visual analog scale of pain from 42.1 to 26.4. ConclusionThese findings indicate that walking with a cane reduces the load and pain on the affected hip joint. The effect of the cane on the trunk lean was small, but it is worth noting that walking with a cane may increase the load on the healthy side.

A Comparison of Three Research Methods: Logistic Regression, Decision Tree, and Random Forest to Reveal Association of Type 2 Diabetes with Risk Factors and Classify Subjects in a Military Population

Background: Type 2 diabetes mellitus (T2DM) is one of the major non-communicable diseases, causing morbidity and mortality worldwide. There is no study on T2DM status in Iran Army Forces. Objectives: We aimed to measure the prevalence of T2DM in this population and identify variables associated with T2DM risk in order to classify individuals. Methods: Data from 3661 Iran Army Ground Forces were employed. Characteristics of the subjects with and without T2DM were compared. We examined the classification ability of logistic regression with two tree-based supervised learning algorithms, decision tree and random forest (RF). The ethical committee of AJA University of Medical Sciences approved this study by the approval code 995685. Results: The prevalence of T2DM was 3% less than in the general population. Our results showed that the incidence of T2DM increases as subjects become older. The proportions of staff members with T2DM were more than the other military ranks. T2DM is more common in obese and overweight groups. The highest prevalence of T2DM is in the subjects with high levels of lipid profile. The areas below the receiver operating characteristic curve for logistic regression, decision tree, and RF were 73.8%, 77.1%, and 97.1%, respectively. Conclusions: Age, body mass index, total cholesterol, low-density lipoprotein cholesterol, and triglyceride are associated with T2DM risk. The RF has superior classification performance in comparison with logistic regression and decision tree.

Вплив авторської програми фізичної підготовки на спортивні результати команд з військового п’ятиборства

The purpose of the study was to determine the impact of the author's program of physical training in military pentathlon on the sports readiness of teams. Materials and methods. To solve the goal, an experimental and control groups were formed, the results of special physical fitness of the subjects were determined, a comparative analysis of the indicators of competitive activity of athletes was carried out. The following methods were used to obtain objective data: theoretical methods (analysis and generalization of literature sources and empirical data); documentary method (analysis of official CISM documents); pedagogical methods (observation, experiment); testing the initial and final levels of general and special physical fitness of athletes; methods of mathematical statistics. The research was conducted in several stages with consistent and parallel solution of work tasks in the period from 2017 to 2019. The first stage (January 2017 – November 2017) was aimed at analyzing and summarizing data from special literature, publications and research. The second stage (November 2017 – November 2019) involved a formative pedagogical experiment, which tested the effectiveness of the author's program of physical training of pentathletes. To test the effectiveness of the experimental training program, experimental (n = 20) and control groups (n = 28) were formed, in which all cadets in military pentathlon had the same level of sports training. The cadets of Hetman Petro Sahaidachnyi National Ground Forces Academy (n = 20) were included in the experimental group, and the cadets of seven high educational institutions of Ukraine (n = 28) – in the control group. The distribution was based on the results of preliminary testing using the method of random sampling. Results and discussion. The results of the study confirmed that it is impossible to achieve high results in military pentathlon without continuous improvement of the organization, content and methods of implementation of this pedagogical process in the stages of preparation of military athletes for competitions. It is confirmed that one of the leading reasons for improving performance is related to the transfer of the training effect, namely the positive and sensitive period, which is characteristic of these physical qualities at the age stage in which the subjects were. Other reasons were related to the used load parameters planning, means and methods of training. The sports result of experimental group, namely the level of special physical fitness of the military pentathletes of the National Armed Forces in the conditions of the physical training program, significantly improved in the first (5.8%, p &lt;0.05) and second (6.1%, p &lt;0.05) stages of the study and as a result significantly increased by 11.5% (p &lt;0.01). On the other hand, in the control groups 1-7 the tendency to increase sports results was not confirmed statistically. Conclusion. It has been proved that the author’s program of physical training of athletes in military pentathlon in the high educational institutions of the Armed Forces of Ukraine is not inferior to the traditional one in terms of efficiency. Significant differences (p &lt;0.05 – p &lt;0.001) in the amount of points scored at the Championship of the Armed Forces of Ukraine in military pentathlon between the participants of experimental and control groups (control group 1, control groups 3-7) after the end of the pedagogical experiment were determined

Automatic Speech Recognition Training Software for Joint Terminal Attack Controller Close Air Support Requests

Close air support (CAS) is a crucial element of joint fire support that requires intricate planning, coordination, and training of various ground and supporting air forces for safe and effective execution. Based on the nature of the target and the availability of additional fire support, synchronizing CAS in time, space, and purpose with supported ground forces is one of the most detailed and continuous integration tasks performed in concert by the joint force, component commanders, and staffs (Joint Publication, 2014). Using SpeechZero, a novel interface that allows non-expert users to customize Automated Speech Recognition (ASR) systems for Department of Defense training applications, SoarTech is creating a training software for Joint Terminal Attack Controller (JTAC) CAS requests. These requests follow a structured verbal protocol called a 9-line. The training software utilizes ASR and generation, which allows trainees to practice verbal communication skills in representative training environments without the need for human role players. However, these technologies have yet to become a feature of most training systems. Using SoarTech’s SpeechZero ASR software, an individual speaks their 9-line request into a tablet or smartphone which will parse the speech and use AI algorithms to categorize it within the 9-line framework. The utilization of this software for CAS 9-line requests has the potential to produce more effective training and documentation of CAS events which is critical in ensuring the safety of civilians and friendly forces alike.&#x0D; References&#x0D; Joint Publication (JP) 3-09.3. Close Air Support, 25 November 2014.

Ground effect for ducted wind turbines: A computational study

Ducted wind turbines (DWTs) can take the advantage of ground effect (GE) when installed close to urban areas. To this aim, a parametric study to investigate the aerodynamic performance of DWTs in relation to three different ground distances are investigated. The flow around a commercial DWT model using a simplified duct actuator disc (AD) model based on Reynolds Averaged Navier-Stokes (RANS) equations is performed. The results indicate that DWTs placed close to the ground will lead to increased mass flow rate the turbine plane, and thereby improving the aerodynamic performance. However, the additional ground force leads to an asymmetric flow-field at the turbine plane, which will ultimately induce unsteady forces on the DWT system. The present analysis will serve as a strong recommendation to address siting issues for DWT manufacturers.

Physiological and kinematic biomarkers for optimal performance and safety in the heat

Introduction: During Arctic operations, the difficulties of safely mobilizing ground forces in extreme cold environments becomes particularly apparent given the high diversity between individuals in morphology, in physiological capabilities, psychological preparedness and in genetic makeup. Understanding potential risk factors for cold weather injuries in individual operators is key to reduce casualties, maintain performance and ensure mission success. The purpose of this research program is to better understand and identify the factors that predict individual physiological and psychological responses to the cold, which may be key to maintain the ability to sustain performance in such environments. Methods: Through an international collaborative effort, our research team has developed a systematic laboratory-based cold evaluation method which includes a detailed characterization of individuals (body shape and composition) and a highly standardized cold test to predict key physiological and psychological markers of cold operational readiness (i.e., shivering, dexterity, risks of developing cold weather injuries, cognitive capacity, mood, thermal comfort, and fatigue). Results: The pilot data confirmed the extremely large variability in cold responses in women and men during the cold test. We also found that body mass may be the greatest determinant for cold tolerance and affects not only the amount of shivering that occurs but also hand temperature and thermal comfort. Conclusions and future research: Systematically identifying key individual biomarkers of cold response is an essential first step in providing individualized cold weather training, proper clothing solutions and operational guidelines. In follow-up work, a cold-weather screening tool will be developed and used during cold weather training and operations to refine the model. Additional laboratory trials will be conducted to refine the cold weather screening tool algorithm in response to these pre-exposure interventions. Such a cold screening tool is essential for adapting training and to determine potential decreases in performance capabilities for Arctic operators.