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The major aim of this research was to understand the effect of the addition of sodium bicarbonate (NaHCO3) on the reaction yield and products in the direct aqueous mineral carbonation of heat-activated lizardite under single-step reaction conditions (130 bar, 150 °C) developed by the Albany Research Center. This was achieved by tracking the evolution of the aqueous and solid species produced over the duration of the reaction. Analysis of solid and liquid samples was performed using a variety of analytical techniques, including thermal gravimetric analysis mass spectrometry, inductively coupled plasma optical emission spectrometry, qualitative and semiquantitative X-ray diffraction analysis, and laser diffraction particle size analysis. Carbonation experiments were conducted with and without NaHCO3using heat-activated lizardite to study its effect on the reaction rate and overall yield. It was found that NaHCO3controlled the magnesium carbonate phase formed in the carbonation reaction [hydromagnesite or magnesite (MgCO3)]. It can be concluded that NaHCO3elevates the concentration of carbonate ions (CO32–), leading to a heightened level of supersaturation in the carbonate phase. This, in turn, contributes to an increased extent of MgCO3precipitation.

One of the most permanent methods of carbon storage is fixing CO2into a solid matrix of carbonate minerals. The most recent reports by the U.S. National Academies and the Mission Innovation presented that carbon mineralization is a CO2utilization technology with a great carbon storage potential and a large market size. While the mineral carbonation reaction is thermodynamically favored, its kinetics has been considered to be too slow without engineered enhancements. Particularly, the formation of the Si-rich passivation layer on mineral particles limits the overall reaction rate by creating a significant diffusion barrier. In this study, a unique internal grinding system was designed by directly incorporating grinding media into the carbon mineralization reactor based on a PCO2(partial pressure of CO2) swing. The effect of physical properties (e.g., sizes and densities) of grinding media on the dissolution behaviors of heat-treated Mg-silicate minerals (i.e., serpentine, Mg3Si2O5(OH)4) was investigated. The stress intensity, which is proportional to the energy transferred from grinding media to the heat-treated serpentine particles during a stress event, was used to describe the effect of the reaction parameters on the extent of the physical activation and the enhancements in mineral dissolution. The existence of the optimum stress intensity was identified where the minimum particle size was obtained. It was found that two attrition modes, abrasion and fragmentation/pulverization, were dominant depending on the stress intensity and that the fragmentation/pulverization mode was more effective in removing the Si-rich passivation layer and promoting Mg extraction during the dissolution step. The internal grinding system resulted in greater Mg leaching compared to the conventional ex situgrinding because the in situapproach allowed the synergistic effect of continuous removal of the Si-rich layer and surface dissolution reaction leading to the improved overall energy efficiency of the developed CO2utilization and storage technology.

A study is conducted to quantitatively analyze the effect of repeated cool water ingestion on gastrointestinal (GI) pill temperature. Findings suggest that a GI pill ingested immediately prior to physical activity cannot measure core body temperature accurately during the next 8 hours when cool water is regularly ingested.

Research points out that development of chronic exertional compartment syndrome (CECS) in the anterior tibial compartment due to reduced venous blood flow caused intramuscular pressures can be induced in healthy subjects by external venous occlusion of the anterior tibial compartment. However, the syndrome development follows different paths in CECS patients and healthy subjects.

Experimental data indicate that carbon vacancies incorporated in active regions of SiC devices are important electrical defects, responsible for device limiting effects such as carrier lifetime reduction. For field-effect transistors that include a 4H-SiC/SiO2 interface, such as at the gate, the oxidation pro- cess is understood to introduce native defects to the SiC, including injection of carbon self-interstitials and vacancies, that diffuse into the active layer and interact with other defects and impurities. It is therefore important to understand the migration behaviour of primary native defects such as VC in the vicinity of 4H-SiC/SiO2 interfaces. We report here the results of a density-functional theory investi- gation into the diffusion of the carbon vacancy in such a region. We conclude that the migration of VC is significantly hindered in the immediate vicinity of the interface, with the energy of diffusion barrier being approximately 15% greater than the corresponding diffusion in bulk 4H-SiC.

The purpose of this study, was to investigate strength, failure and recovery of the anterior tibial muscles in chronic exertional compartment syndrome (CECS) patients and healthy subjects during an isometric exercise protocol. CECS patient were somewhat weaker than normal, but fatigued at a similar rate during isometric exercise.

We present a model to describe carbon dioxide (CO2) capture using reactive silicate-based mineral slurries exposed to a gas flow containing CO2. The model is validated through experimentation using thermally conditioned or heat-activated serpentinite (hydrous metamorphic ultramafic rock) in a laboratory-scale bubble column reactor. The kinetic model developed advocates a holistic modeling approach, offering an expanded view of the dissolution of heat-activated serpentinite under lean CO2conditions, in which the gas–liquid–solid system and its influence on CO2dissolution and the coupled dissolution behavior of the material are considered in their entirety. Modeling incorporates the characteristics of the gas to liquid phase interaction, such as CO2composition of the gas phase and interfacial area, the composition of the aqueous phase and its temperature, and compositional and morphological features of the solid. We demonstrate that such an approach is essential when considering proton-limiting conditions that are especially relevant to mineral dissolution under dilute CO2conditions in short reaction timeframes. The model is of particular relevance to the use of reactive silicate-based minerals for the aqueous capture of CO2from dilute CO2gas streams. The model as developed can be used to predict CO2capture using heat-activated serpentinite slurries for a given set of operating conditions and should be adaptable for use with other alkaline materials of defined reactivity in similar or varying reaction settings by adequately specifying reaction conditions.

•Magnesite yield in pilot reactor was 35% higher than in lab reactor.•Pilot reactor configuration improved mixing and magnesite yield.•Surface of reacting particles refreshed due to advanced mixing in pilot reactor.•The effect of 0.64 M sodium bicarbonate on magnesite yield was significant.•Mg extraction in dissolution experiment was similar in pilot and lab reactors.

This study assessed soldier's physical demands and energy balance during the Section Commanders' Battles Course (SCBC). Forty male soldiers were monitored during the 8-week tactics phase of the SCBC. Energy expenditure was measured using the doubly labeled water method. Cardiovascular strain (heart rate) and physical activity (using triaxial accelerometer) were also monitored. Average sized portions of meals were weighed, with all recipes and meals entered into a dietary analysis program to calculate the calorie content. Energy expenditure averaged 19.6 ± 1.8 MJ · d(-1) in weeks 2 to 3 and 21.3 ± 2.0 MJ · d(-1) in weeks 6 to 7. Soldiers lost 5.1 ± 2.6 kg body mass and body fat percent decreased from 23 ± 4% to 19 ± 5%. This average weight loss equates to an estimated energy deficit of 2.69 MJ · d(-1). The Army provided an estimated 14.0 ± 2.2 MJ · d(-1) in weeks 2 to 3 and 15.7 ± 2.2 MJ · d(-1) in weeks 6 to 7. Although this provision adheres to the minimum requirement of 13.8 MJ · d(-1) set by Army regulations, soldiers were in a theoretical 5.6 MJ · d(-1) energy deficit. The physical demands of SCBC were high, and soldiers were in energy deficit resulting in loss in body mass; primarily attributed to a loss in fat mass.

In the United Kingdom, all branches of the armed forces use 2.4-km run time and/or the 20-m multistage shuttle run test (MSRT) to assess the aerobic fitness of their personnel. This study quantified the relationship between these two tests in 156 army recruits and officer cadets (100 men and 56 women) to ensure equivalence in the required aerobic fitness standards. The 2.4-km run was performed on surfaced roads and tracks around the training establishment and the MSRT in a gymnasium. Ordinary least product regression was used to describe the relationship between average 2.4-km running speed (km · h(-1)) and the total number of shuttles completed on the U.K. version of the MSRT (r = 0.91, p < 0.01), showing MSRT shuttles = (9.708×2.4-km run speed) - 52.56, with a standard error of prediction of approximately 8 shuttles or 0.8 km · h(-1). The British Army 2.4-km run biannual fitness assessment standard for young men of 10:30 min:s equates to a MSRT score of 82 shuttles (level 10 and 1 shuttle) and for young women of 13:00 min:s equates to 56 shuttles (level 7 and 6 shuttles), with a standard error of estimate of approximately 8 shuttles.

Density functional calculations are used to perform a systematic study of the effect of edge-functionalization on the structure and electronic properties of graphene nanoribbons (GNRs). −H, −F, −Cl, −Br, −S, −SH, and −OH edge-functionalization of armchair, zigzag, and reconstructed Klein-type GNRs was considered. The most energetically favorable edge structure varies depending on the choice of functional group. It is shown, for the first time, that reconstructed Klein-type GNRs are important stable configurations for several edge-functional groups. Band gaps using three different exchange-correlation functionals are calculated. The band gap for armchair GNRs can be tuned over a range of ∼1.2 eV by varying the edge-functional groups. In contrast, the band gaps of zigzag and reconstructed Klein edge GNRs are largely insensitive to the choice of edge-functional group, and ribbon width is instead the defining factor. Alternatively, the armchair GNR band gap can be controlled by varying the number of functional groups per opposing edge, altering the GNR “effective” width. Edge-functionalization design is an appropriate mechanism to tune the band gap of armchair GNRs.

Diamond surfaces with suitable adsorbed chemical species can exhibit both negative and positive electron affinities, arising from the complex electrostatic interplay between adsorbates and surface carbon atoms of diamond lattice. We presents the results of density functional calculations into the energetics and the electron affinity of diamond (100) surfaces terminated with the oxides of selected transition metals. We find that for a correct stoichiometry, oxides of transition metals, such as Ti and Zn, exhibit a large negative electron affinity of around 3 eV. The desorption of transition metal oxides is found to be highly endothermic. We therefore propose that transition metal oxides are promising for the surface coating of diamond-based electron emitters, as these exhibit higher thermal stability in comparison to the commonly used CsO terminations, while retaining the advantage of inducing a large negative electron affinity.

The radial dependence of the formation energy of substitutional phosphorus in silicon nanoparticles covered by an amorphous oxide shell is analysed using local density functional theory calculations. It is found that P+is more stable at the silicon core. This explains the experimental observation of segregation of phosphorus to the Si‐rich regions in a material consisting of Si nanocrystals embedded in a SiO2matrix [Perego et al., Nanotechnology 21, 025602 (2010)].

We analyse the formation energy of interstitial boron (Bi) and the properties of the defect resulting from its association with an oxygen dimer (BiO2i) to evaluate the possibility that it may be the slow‐forming centre responsible for the light‐induced degradation of B‐doped Si solar cells. However, we find that the formation energy of Biis too high, and therefore its concentration is negligible. Moreover, we find that the lowest energy form of BiO2iis a shallow donor, and the deep donor form is high in energy.

This study compared the physical demands and progression of basic training for male and female British Army recruits in single-sex platoons. Thirty male and 30 female recruits were monitored for energy expenditure (EE) (doubly labeled water), physical activity (3-dimensional accelerometry) and cardiovascular strain (percent heart rate reserve) during 6 weeks over the 14-week course. First time pass rate was similar for male (60%) and female (57%) recruits. Average daily percent heart rate reserve (female 31 +/- 4%; male 32 +/- 5%), physical activity levels (female 2.2 +/- 0.2; male 2.3 +/- 0.2) and percentage improvements in 2.4-km run time (female 10 +/- 4%; male 10 +/- 5%) were similar for both sexes (p > 0.05), although male recruits had 12% higher physical activity counts (p < 0.01). Although the absolute physical demands of basic training were greater for male recruits, the relative cardiovascular strain experienced was similar between sexes.

Substitutional group III and group V elements, though commonly used as shallow dopants in bulk silicon, have a limited efficiency in silicon nanocrystals. In this work, we use first-principles models of 1.5 nm nanocrystals with hydride- and silanol-terminated surfaces to understand how oxidation influences the segregation and deactivation of dopants at the surface and the dopant binding energies. We show that the surface oxygen layer changes drastically the radial dependence of the dopant formation energy both for donors and for acceptors, but that, independently from the oxidation, dopant diffusion does not take place at operating conditions. Additionally, we show that the oxidation increases the electron binding energy of the P, As, and Sb and decreases the hole binding energy of B, Al, Ga, and In.

To quantify the health, fitness, and physiological responses to military training of Officer Cadets from a Gulf Cooperation Council country.

We have recently shown that Sn impurity atoms are effective traps for vacancies (V) in Ge:Sn crystals irradiated with MeV electrons at room temperature [V.P. Markevich et al., J. Appl. Phys. 109 (2011) 083705]. A hole trap with 0.19 eV activation energy for hole emission to the valence band (Eh) has been assigned to an acceptor level of the Sn-V complex. In the present work electrically active defects introduced into Ge:Sn+P crystals by irradiation with 6 MeV electrons and subsequent isochronal annealing in the temperature range 50-300 oC have been studied by means of transient capacitance techniques and ab-initio density functional modeling. It is found that the Sn-V complex anneals out upon heat-treatments in the temperature range 50-100 oC. Its disappearance is accompanied by the formation of vacancy-phosphorus (VP) centers. The disappearance of the VP defect upon thermal annealing in irradiated Sn-doped Ge crystals is accompanied by the effective formation of a defect which gives rise to a hole trap with Eh = 0.21 eV and is more thermally stable than other secondary radiation-induced defects in Ge:P samples. This defect is identified as tin-vacancy-phosphorus (SnVP) complex. It is suggested that the effective interaction of the VP centers with tin atoms and high thermal stability of the SnVP complex can result in suppression of transient enhanced diffusion of phosphorus atoms in Ge.

This study examined gender differences in the physical demands of British Army recruit training in 3 platoons with different gender compositions. Subjects wore heart rate monitors to measure cardiovascular strain and accelerometers to measure physical activity during weeks 1, 6, and 9 of the 12-week program. There was no difference in physical activity between platoons or genders (p > 0.05). In the mixed gender platoon, males operated at a lower cardiovascular strain than females (24 +/- 2 vs. 33 +/- 2% heart rate reserve (HRR), p < 0.001), probably because of their greater aerobic fitness (p < 0.001). Males in the mixed gender platoon experienced lower cardiovascular strain than the male-only platoon (24 +/- 2 vs. 33 +/- 2% HRR, p < 0.001). Females experienced the same degree of cardiovascular strain, irrespective of platoon (33 +/- 2 vs. 33 +/- 3% HRR, p = 0.814). The additional cardiovascular strain experienced by female recruits may increase fatigue and predisposition to overuse musculoskeletal injury.

This study aimed to identify risk factors for training injuries resulting in referral to a remedial instructor (RI) or medical discharge (MD) among British Army recruits undertaking initial training. Physical performance and anthropometric data for 11,937 male and 1,480 female recruits were examined as potential risk factors for RI referral and MD, using Cox regression. There was a trend showing that female recruits' MD rates were higher than male recruits' rates (p = 0.096), and RI referral rates were significantly greater for women than for men (p = 0.041). The independent risk factors for MD were 2.4-km run time, ethnicity, and Army training regiment attended (p < 0.001), and those for RI referral were 2.4-km run time, ethnicity, Army training regiment attended, and body mass index (p < 0.001). Gender was not an independent risk factor for injury, suggesting that lower levels of aerobic fitness are the primary cause of the greater incidence of injury among female recruits during British Army initial training.

The objective of this research was to determine whether tests of strength, endurance, and anthropometry could be used to assess training-induced changes (delta) in load-carriage performance. Eighty-four British Army recruits completed a 10-week training program. Strength, endurance, body composition, and 3.2-km load carriage with 15 kg and 25 kg were assessed before and after training. Training significantly increased load-carriage performance (7-16%), back extension and dynamic lifting strengths, endurance and fat-free mass, and reduced body fat. Statistically significant regression models (adjusted R2 of 0.063-0.797) were produced that predicted delta load-carriage performance. However, the 95% limits of agreement between observed and predicted delta load-carriage data showed margins of error (11-15%) comparable to the average training-induced gains in performance. Training-induced changes in load-carriage performance appear to be highly specific, which suggests that both training and testing procedures should also be specific to load-carriage performance.

The carbon vacancy in bulk 4H‐SiC and in the vicinity of an SiO2/(0001)‐4H‐SiC interface using density‐functional theory is studied. It is found that the migration is hindered in the immediate vicinity of the interface, with the energy barrier for diffusion being ≈15% greater than the same defect in bulk 4H‐SiC. Herein, it is shown that the increased barrier is a consequence of the stabilization of the vacancy in the immediate interface due to a combination of strengthened reconstructions and interfacial relaxation, coupled with the destabilization of the transition‐state structure. The majority of electronically active defects in SiC are located deep within the bandgap, thereby degrading the carrier transport properties of SiC. This study compares the diffusion of a carbon vacancy in different (0001)‐layers relative to a SiO2/SiC interface using the density‐functional theory simulations. The results show that vacancies in the upper layers are stabilized due to stronger bonding and interfacial relaxation.