Perspectives on the Terrestrial Organic Matter Transport and Burial along the Land-Deep Sea Continuum: Caveats in Our Understanding of Biogeochemical Processes and Future Needs

The natural carbon cycle is immensely intricate to fully understand its sources, fluxes and the processes that are responsible for their cycling in different reservoirs and their balances on a global scale. Anthropogenic perturbations add another dimension to such a complex cycle. Therefore, it is necessary to update the global carbon cycle by combining both natural and anthropogenic sources, fluxes and sinks along the land-sea continuum to assess whether these terms are currently in balance or not. Here, we review the export and it burial rates of terrestrial organic carbon in the oceans to understand the issue of missing terrigenous carbon by comparing data- and model-based estimates of terrestrial carbon fluxes. Our review reveals large disparities between field-based data and model output in terms of dissolved and particulate organic carbon/matter (OC/OM) fluxes and their ratios, especially for Oceania and Arctic rivers, suggesting the need of additional investigations in these regions to refine terrestrial OC export budget. Based on our budgeting of global sources and sinks of OC with updated estimates of marine productivity and terrestrial OM burial rate, we find that the marginal sediments are key burial sites of terrestrial OM, which is consistent with earlier views of Berner (1982) and Hedges and Keil (1995). While about 60‒80% of TOM is remineralized in the margins, the estimated budget further reveals the ocean derived OM is efficiently remineralized than that of terrestrial OM, emphasizing the need of further improvements of carbon burial estimation in the marine realm. When we look back in the past, higher terrestrial OC burial (by ~50%) in the deep ocean during the glacials than during the interglacials suggests the subdued role of continental margins and an efficient transfer of OM from the shelf to deep sea in glacials. Based on the review of terrestrial and marine OM burial, we suggest some critical regions/ways that need to be investigated/addressed further, identification of new biogeochemical proxies and their grouping to better constrain the global carbon cycle along the land-deep sea continuum in future

Hazardous Processes and Their Risk Mitigation Techniques in Iron and Steel Industry Emission in CFB Boiler- A Review

Steel manufacturing industries are one of the major industries in the world where number of hazards are being involved in Daily work practices. While working in such steel industries safe operating/work procedures are too much significant as employees are exposed to various threats due to nature of job and work operations. For any industry labour is considered as a great asset which follows the work as trades. As per the New Occupational Safety and Health CODE – Hazardous Process is mentioned in two ways (i) consequence in toxic waste of universal atmosphere or (ii) reason material injury to health of a worker occupied [1]. The working environment in steel industry is too much noisy with excessive heat. In today’s world most of the steel industries are using new technologies where control systems are used in various steel manufacturing industries to control number of incidents and accidents and have precise control over steel composition addition which reflects the quality. As the safety is being considered paramount in today’s working environment, so regardless the hazardous process of various steel manufacturing industries achieving an accident free environment is achievable. Several Risk Assessment Techniques like Hazard Identification and Risk Assessment (HIRA) Techniques/Job Safety Analysis are used to reduce the work place injuries i.e. Frequency rate, severity rate and incident rate statistically and statistics of several years has been studied on the various mentioned process and injuries resulting in ill-health is mitigated [2]

Effect of Anatase and Rutile Phase Microspheres Composition on Dye-Sensitized Solar Cell Photoanode Performance

126-130The effect of calcination temperature on the phase stability of solvothermally synthesized mesoporous anatase TiO2 microspheres has been investigated through X-ray diffraction and Raman spectroscopy. Morphological change owing to anatase to rutile phase transformation has been examined by transmission electron microscopy. Dye-sensitized Solar Cell with anatase TiO2 microspheres photoanode exhibits good photovoltaic performance with an overall cell efficiency of 4.47 %. Calcination above 900 °C reduces the efficiency. Incident Photon to Current Conversion Efficiency (IPCE) studies reveals that the TiO2 microspheres calcined at 700 °C have high IPCE due to high dye loading owing to its high surface area and porous structure

Fracture performance of externally FRP strengthened reinforced concrete beams mixed with rigid fibres

Posljednjih desetljeća opsežno su provođena eksperimentalna istraživanja na armiranobetonskim (AB) gredama pojačanim vlaknima. Utvrđena je učinkovitost u području pojačanja na savijanje i posmik. S druge strane, primarni problem koji se često susreće u takvoj tehnici jest odvajanje FRP laminata od betonske površine. Takva otkazivanja nastaju zbog formiranja lokaliziranih savojnih i posmičnih pukotina u krhkom području FRP betona. Pojava odvajanja također značajno utječe na povećanje nosivosti pojačanih greda. Težište istraživanja je poboljšati potencijalno ponašanje izvana pojačanih AB greda FRP-om dodavanjem učinkovitog sredstva za kontrolu pukotina u matricu, a to su “kruta čelična vlakna s kukastim krajevima”. Izvedeno je devet AB greda i ispitano u ovom istraživanju s varijablama uključujući različite količine čeličnih vlakana s kukastim krajevima i debljinu polimera armiranih staklenim vlaknima. Ponašanje izvana FRP-om pojačanih AB greda pomiješanih s kratkim vlaknima prije i nakon raspucavanja sustavno je procijenjeno i utvrđeno je poboljšano djelovanje u različitim fazama raspucavanja. Drugo otkriće je transformacija oblika loma iz krtog u duktilni zbog izuzetnog fenomena deformacijskog očvršćivanja uzrokovanog čeličnim vlaknima u pojačanim AB gredama, u usporedbi s ostalim gredama bez čeličnih vlakana. Formiranje i širenje pukotina u različitim fazama numerički je modelirano za sve grede uporabom ANSYS-a i uspoređena je validacija numeričkog modela s eksperimentom.In recent decades experimental investigations on fibre reinforced polymer (FRP) laminate-strengthened reinforced concrete (RC) beams have been extensively conducted. It has been found effective in flexural and shear strengthening perspectives. On the other hand, a primary problem frequently encountered in such technique is the separation of FRP laminate with the concrete bonded surface. Such failures are due to the formation of localized flexural and otherwise shear cracks in the fragile region of the FRP-concrete interface. The debonding occurrence also significantly affects the strength enhancement of the laminated beams. The emphasis of the study is to enhance the potential performance of externally FRP strengthened RC beams by incorporating an effective crack controlling agent, that is ‘rigid hooked-end steel fibres’ in the matrix. Nine RC beams were cast and tested in this study with variables including different quantities of hooked-ends steel and glass fibre reinforced polymer (GFRP) thickness. The pre-cracking and post-cracking behaviour of the externally FRP strengthened RC beams mixed with the short fibres were systematically evaluated and improved performance at various stages of cracking was found. Another finding is the transformation of failure pattern from brittle to ductile due to exceptional strain-hardening phenomenon caused by steel fibres in the strengthened RC beams, in comparison to that of other beams without steel fibres. The formations and propagations of the cracks at different stages were numerically modelled for all the beams using the ANSYS and compared the numerical design validation with the experiment

Millennial-scale variations in sedimentary oxygenation in the western subtropical North Pacific and its links to North Atlantic climate

The deep-ocean carbon cycle, especially carbon sequestration and outgassing, is one of the mechanisms to explain variations in atmospheric CO2 concentrations on millennial and orbital timescales. However, the potential role of subtropical North Pacific subsurface waters in modulating atmospheric CO2 levels on millennial timescales is poorly constrained. An increase in the respired CO2 concentration in the glacial deep-ocean due to biological pump generally corresponds to deoxygenation in the ocean interior. This link thus offers a chance to study oceanic ventilation and coeval export productivity based on redox-controlled sedimentary geochemical parameters. Here, we investigate a suite of geochemical proxies in a sediment core from the Okinawa Trough to understand sedimentary oxygenation variations in the subtropical North Pacific over the last 50 000 years (50 ka). Our results suggest that enhanced mid-depth western subtropical North Pacific (WSTNP) sedimentary oxygenation occurred during cold intervals and after 8.5 ka, while oxygenation decreased during the Bölling-Alleröd (B/A) and Preboreal. The enhanced oxygenation during cold spells is linked to the North Pacific IntermediateWater (NPIW), while interglacial increase after 8.5 ka is linked to an intensification of the Kuroshio Current due to strengthened northeast tradewinds over the tropics. The enhanced formation of the NPIW during Heinrich Stadial 1 (HS1) was likely driven by the perturbation of sea ice formation and sea surface salinity oscillations in the high-latitude North Pacific. The diminished sedimentary oxygenation during the B/A due to a decreased NPIW formation and enhanced export production, indicates an expansion of the oxygen minimum zone in the North Pacific and enhanced CO2 sequestration at mid-depth waters, along with the termination of atmospheric CO2 concentration increase. We attribute the millennial-scale changes to an intensified NPIW and enhanced abyss flushing during deglacial cold and warm intervals, respectively, closely related to variations in North Atlantic Deep Water formation

Exploring the Anti-bacterial Potential of Orchid-derived Silver Nanoparticles

In this study, silver nanoparticles (AgNPs) were synthesized in an environmentally friendly manner using plant extracts from Luisia tristis. The formation of the nanoparticles was confirmed by a reddish-brown colour change and further characterized using ultraviolet–visible (UV–Vis), Fourier transform infrared spectrometer (FTIR), scanning electron microscope (SEM), and transmission electron microscope (TEM) techniques. The average size of the particles was found to be 16–48 nm. The antimicrobial activity of the AgNPs was evaluated against harmful bacteria and compared to the commonly used antibiotic ciprofloxacin. The AgNPs were found to be highly effective, with a 24 mm zone of inhibition against Escherichia coli, and more effective than ciprofloxacin. Additionally, a minimum inhibitory concentration assay was performed with a concentration of 100 mg/mL of AgNPs, which were found to effectively inhibit the growth of selected pathogens. Overall, the study demonstrates the potential for using plant-derived AgNPs as a natural and eco-friendly alternative for antimicrobial and antioxidant applications. This method is a fast, cost-effective way to generate silver nanoparticles at room temperature and may be useful in creating environmentally friendly antibacterial solutions for biomedical applications

A global multiproxy database for temperature reconstructions of the Common Era

Source at https://doi.org/10.1038/sdata.2017.88 .Reproducible climate reconstructions of the Common Era (1 CE to present) are key to placing industrial-era warming into the context of natural climatic variability. Here we present a community-sourced database of temperature-sensitive proxy records from the PAGES2k initiative. The database gathers 692 records from 648 locations, including all continental regions and major ocean basins. The records are from trees, ice, sediment, corals, speleothems, documentary evidence, and other archives. They range in length from 50 to 2000 years, with a median of 547 years, while temporal resolution ranges from biweekly to centennial. Nearly half of the proxy time series are significantly correlated with HadCRUT4.2 surface temperature over the period 1850–2014. Global temperature composites show a remarkable degree of coherence between high- and low-resolution archives, with broadly similar patterns across archive types, terrestrial versus marine locations, and screening criteria. The database is suited to investigations of global and regional temperature variability over the Common Era, and is shared in the Linked Paleo Data (LiPD) format, including serializations in Matlab, R and Python