Floating Structure with Stabilised Buoyancy Control Device for Photovoltaic Application

Conventional approach of energy derivation is causing anthropogenic pollution and climate change. Various sustainable alternatives of renewable energy particularly solar energy have been developed and implemented as a part of the global effort to gradually decommission usage of fossil fuel and in turn, reduce carbon footprint to overcome adverse environmental impacts. Nevertheless, it was reported that in 2019, only 0.85% of total energy used globally is powered by solar energy. Photovoltaic by itself is not feasible enough due to magnified requirement of land for its installation. Therefore, one of the solutions is floating photovoltaic. However, floating photovoltaic is also restraint by the impact of tidal wave. Characterisation of relationship between stability of large floating structures corresponding to volumetric displacement of the buoyancy control device is the focal point of this paper. Significance of tidal wave impact is empirically assessed based on a scaled-down model of buoyancy control device integrated large floating structure by manipulating the buoyancy of buoyancy control device assisted structure to structure without buoyancy control device under a controlled environment. Fluctuation of the buoyancy control device can be reduced by up to 99.65% when tested against highest configuration of wave transducer by displacing only 50% of air with water. Meanwhile, neutral buoyancy is achieved up to almost 100% when the buoyancy control device is completely filled with water and total submergence has been achieved.

CAPE - A link amid thermodynamics and microphysics for the occurrence of severe thunderstorms

Lkkj & bl 'kks/k&i= dk mÌs’; dksydkrk ¼22°32¢] 88°20¢½ esa ekulwu iwoZ _rq ¼vizSy&ebZ½ ds nkSjku xtZ ds lkFk vkus okys Hkh"k.k rwQkuksa dh mRifÙk vkSj fodkl esa lgk;d es?k dh lw{e HkkSfrdh; izfØ;kvksa dh tk¡p djuk gSA bl v/;;u ls ;g irk pyk gS fd dksydkrk esa ekulwu&iwoZ _rq ds nkSjku xtZ ds lkFk vkus okys Hkh"k.k rwQkuksa ds nkSjku rkixfrdh;] xfrdh;] es?k dh lw{e HkkSfrdh vkSj fctyh pdeus dks J`a[kykc) djus esa laoguh; miyC/k foHko ÅtkZ ¼lh- ,- ih- bZ-½ lgk;d gSA bl v/;;u ls izkIr gq, ifj.kkeksa ls ;g irk pyk gS fd dksydkrk esa laoguh; miyC/k foHko ÅtkZ 1000 twYl izfr fd- xzk- ds Hkhrj izcy ikbZ xbZ tks eqDr laogu Lrj ¼,y- ,Q- lh-½ ls Åij fu/kkZfjr nkc Lrjksa ds Hkhrj ikbZ xbZ vkSj ok;q dh viMªk¶V xfr ds ln`’k eku fu"izHkkoh mRIykodrk Lrj ¼,y- ,u- ch-½ esa yxHkx 30 - 50 eh-@ lsdsaM ik, x,A bl v/;;u ls ;g Hkh irk pyk gS fd 5 fe- eh- rd ds O;kl ds vkdkj dh c¡wns fLFkj jg ldrh gS ftlds ckn vkdkj c<+us ds dkj.k cw¡nsa VwV tkrh gSaA tc cw¡n dh f=T;k 2-5 fe- eh- ls 3 fe- eh- dh ifjf/k esa gksrh gS rc cw¡nksa dk VwVuk 'kq: gks tkrk gS vkSj 3 fe- eh- ls 5 fe- eh- dh ifjf/k esa cw¡nksa ds VwVus dh laHkkouk vf/kd gksrh gS D;ksfd bl fLFkfr esa cw¡nksa ds yxkrkj VwVus dh dkj.k mudk thoudky cgqr NksVk gks tkrk gSA The aim of the present paper is to view the cloud microphysical processes entailed in the genesis and the development of the severe thunderstorms of pre-monsoon season (April - May) over Kolkata (22°32', 88°20'). The study shows that Convective Available Potential Energy (CAPE) is instrumental in establishing a linkage among thermodynamics, dynamics, cloud microphysics, and lightning during severe thunderstorm of pre monsoon season over Kolkata. The results of the present study reveal that for the thunderstorms reported over Kolkata, CAPE are found to be predominantly within 1000 joules per kgs within the prescribed pressure levels above the Level of Free Convection (LFC) and the corresponding values of the updraft speeds of the air are found to be nearly 30 - 50 m/s at the Level of Neutral Buoyancy (LNB). The study also depicts that the drops may grow up to the size of 5mm in diameter stably, beyond which, they tend to breakup due to the large drop instability. The breakup or splitting is observed to initiate when the drop radius is within the range of 2.5mm to 3mm and the breakup is most likely within the range of 3mm to 5mm because at this stage the lifetime of the drops are short due to the spontaneous breakup.

Design of Light Weight-Low Cost Remotely Operated Underwater Vehicle

Remotely Operated Underwater Vehicles (ROV) currently have been utilized for scientific and commercial applications. Many industries are involved in developing robots in order to reduce human effort as well as increase productivity, efficiency, and monitoring. That said, the need to optimize the cost for design of ROVs became popular. In the present work, a simplified design procedure of a low cost-light-weight ROV is proposed. The design overview includes a description of the three thrusters operated by bilge pump electric motors. The ROV contains only a camera, an IMU and a GPS sensor. The ROV is wired to a control station that is equipped with a screen with a GUI, a joystick and a keyboard to monitor and control the ROV. The design is optimized to achieve a neutral buoyancy force in order to reduce the stabilizing effort during operation, hence reducing energy consumption. The drag force, lift force, drag center, lift center and fluid velocity contours are predicted using a CFD tool. Dynamic analysis including thrust and drag forces in longitudinal, vertical and yaw directions of motion are investigated to facilitate selection of the prime movers. Finally, the control strategy and electrical system description is presented. The proposed methodology proved that a satisfactory performance with an optimized design is achievable. The ROV design presented could be used in quick and low cost inspection of ships.

Exercise-Related Effects on Executive Functions During a Simulated Underwater Extravehicular Activity

Objective Investigation of cognitive performance during extravehicular activities (EVAs) in a space-analog setting. Background EVAs performed by humans in microgravity on the International Space Station (ISS) call for high cognitive performance during upper-body workload. Higher cardiovascular demands interact with cognitive performance, but no knowledge exists about EVA’s special requirements. This study simulates EVA-training underwater to investigate its effects on the executive functions inhibition and switching. Method In a counterbalanced crossover design, 16 divers (age: 28 ± 2.4 years; eight females) performed two conditions (i.e., EVA vs. Inactivity [INACT]) in 3–5 m submersion (diving gear; not in a space-suit). EVA included 30 min of moderate-, followed by 30 min of high-intensity upper-body exercise intervals, paired with EVA-specific cognitive-motor tasks. INACT included no exercise in submersion and neutral buoyancy. Both conditions included cognitive testing at pre, mid (after the first 30 min), and post (after the second 30 min) on a tablet computer. Reaction times (RTs) and response accuracy (ACC) were calculated for both tasks. Results ACC was significantly lower during EVA compared with INACT for inhibition (post: p = .009) and switching (mid: p = .019) at post ( p = .005). RTs for inhibition were significantly faster during EVA ( p = .022; ηp 2 = 0.320). Conclusion Specific physical exercise, intensity, duration, and tasks performed during the EVA might differently affect the exercise-cognition interaction and need further investigation, especially for future long-term space travel. Application Future research might serve to improve mission success and safety for EVAs and long-term space travel.

Identification of Two New Hydrothermal Fields and Sulfide Deposits on the Mid-Atlantic Ridge as a Result of the Combined Use of Exploration Methods: Methane Detection, Water Column Chemistry, Ore Sample Analysis, and Camera Surveys

In 2018–2020 the research vessel (R/V) Professor Logachev (cruises 39 and 41) carried out geological and geochemical studies in the bottom waters of the Mid-Atlantic Ridge hydrothermal fields at 14°45’ N, 13°07’ N, and 13°09’ N. Two new hydrothermal fields were discovered—the Molodezhnoye and Koralovoye. Standard conductivity, temperature, and depth (CTD) sounding with a methane sensor was accompanied by video surveillance and sampling of rocks and water. The rocks were characterized by a zonal composition with opal and sulfides of copper and zinc. An increase in methane concentration values was accompanied by CTD anomalies in the bottom waters. The methane anomaly was formed within the hydrothermal plume of both high-temperature and low-temperature systems. Methane was almost absent in the plume of neutral buoyancy and was associated in all the studied manifestations with the ascending flow of hot waters over the hydrothermal vents. The hydrothermal plumes were characterized by increased Cu, Zn, and Fe concentrations at background Mn concentrations. Signs of low-temperature hydrothermal activity were also observed. Different sources and mechanisms are required to explain the elevated concentrations of base metals and methane in the hydrothermal plumes.

Supersaturation, buoyancy, and moist convective dynamics

Motivated by recent discussions concerning differences of convective dynamics in polluted and pristine environments, the so-called convective invigoration in particular, this paper provides an analysis of factors affecting convective updraft buoyancy, such as the in-cloud supersaturation, condensate and precipitation loading, and entrainment. We use the deep convective period from simulations of daytime convection development over land discussed in our previous publications. An entraining parcel framework in used in the theoretical analysis. We show that for the specific case considered here finite (positive) supersaturation noticeably reduces pseudo-adiabatic parcel buoyancy and cumulative CAPE in the lower troposphere. This comes from keeping a small fraction of the water vapor in a supersaturated state and thus reducing the latent heating. Such a lower-tropospheric impact is comparable to the effects of the condensate loading and entrainment in the idealized parcel framework. For the entire tropospheric depth, loading and entrainment have a much more significant impact on the total CAPE. For instance, an increase in the fractional entrainment rate from 0.05 km−1 to 0.3 km−1 reduces the theoretical level of neutral buoyancy from the upper to the middle troposphere and CAPE by a factor of 4. For the cloud model results, we compare ensemble simulations applying either a bulk microphysics scheme with saturation adjustment or a more comprehensive double-moment scheme with supersaturation prediction. The diagnosed bulk fractional entrainment rate, independent of the microphysics scheme applied in the simulations, is either 0.13 or 0.20 km−1 depending on whether we consider profiles of the upper end of the percentile range or of the mean in-cloud equivalent potential temperature. We compare deep convective updrafts, buoyancies, and supersaturations from all ensembles. In agreement with the parcel analysis, the saturation adjustment scheme provides noticeably stronger updrafts in the lower troposphere. For the simulations predicting supersaturation, there are small differences between pristine and polluted conditions below the freezing level that are difficult to explain by standard analysis of the in-cloud buoyancy components. By applying the piggybacking technique, we show that the lower-tropospheric buoyancy differences between pristine and polluted simulations come from a combination of temperature (i.e., latent heating) and condensate loading differences that work together to make polluted buoyancies and updraft velocities slightly larger when compared to their pristine analogues. Overall, the effects are rather small and contradict previous claims of a significant invigoration of deep convection in polluted environments.