A critical review on sustainable biochar system through gasification: energy and environmental applications

This review lays great emphasis on production and characteristics of biochar through gasification. Specifically, the physicochemical properties and yield of biochar through the diverse gasification conditions associated with various types of biomass were extensively evaluated. In addition, potential application scenarios of biochar through gasification were explored and their environmental implications were discussed. To qualitatively evaluate biochar sustainability through the gasification process, all gasification products (i.e., syngas and biochar) were evaluated via life cycle assessment (LCA). A concept of balancing syngas and biochar production for an economically and environmentally feasible gasification system was proposed and relevant challenges and solutions were suggested in this review

Enhanced catalytic soot oxidation by Ce-based MOF-derived ceria nano-bar with promoted oxygen vacancy

As CeO2 is a useful catalyst for soot elimination, it is important to develop CeO2 with higher contact areas, and reactivities for efficient soot oxidation and catalytic soot oxidation are basically controlled by structures and surface properties of catalysts. Herein, a Ce-Metal organic framework (MOFs) consisting of Ce and benzene-1,3,5-tricarboxylic acid (H3BTC) is employed as the precursor as CeBTC exhibits a unique bar-like high-aspect-ratio morphology, which is then transformed into CeO2 with a nanoscale bar-like configuration. More importantly, this CeO2 nanobar (CeONB) possesses porou, and even hollow structures, as well as more oxygen vacancies, enabling CeONB to become a promising catalyst for soot oxidation. Thus, CeONB shows a much higher catalytic activity than commercial CeO2 nanoparticle (comCeO) for soot oxidation with a significantly lower ignition temperature (Tig). Moreover, while soot oxidation by comCeO leads to production of CO together with CO2, CeONB can completely convert soot to CO2. The tight contact mode also enables CeONB to exhibit a very low Tig of 310 °C, whereas the existence of NO also enhances the soot oxidation by CeONB to reduce the Tig. The mechanism of NO-assisted soot oxidation is also examined, and validated by DRIFTS to identify the formation and transformation of nitrogen-containing intermediates. CeONB is also recyclable over many consecutive cycles and maintained its high catalytic activity for soot oxidation. These results demonstrate that CeONB is a promising and easily prepared high-aspect-ratio Ce-based catalyst for soot oxidation

Advances in green chemistry and engineering

Abstract Green chemistry and engineering seek for maximizing efficiency and minimizing negative impacts on the environment and human health in chemical production processes. Driven by advances in the principles of environment protection and sustainability, these fields are expected to greatly contribute to achieving sustainable development goals. To this end, many studies have been conducted to develop new approaches within green chemistry and engineering. The Advances in Green Chemistry and Engineering Collection at Scientific Reports aims at gathering the latest research on developing and implementing the principles of green chemistry and engineering

Recent Advances in Renewable Polymer Production from Lignin-Derived Aldehydes

Lignin directly derived from lignocellulosic biomass has been named a promising source of platform chemicals for the production of bio-based polymers. This review discusses potentially relevant routes to produce renewable aromatic aldehydes (e.g., syringaldehyde and vanillin) from lignin feedstocks (pre-isolated lignin or lignocellulose) that are used to synthesize a range of bio-based polymers. To do this, the processes to make aromatic aldehydes from lignin with their highest available yields are first presented. After that, the routes from such aldehydes to different polymers are explored. Challenges and perspectives of the production the lignin-derived renewable chemicals and polymers are also highlighted

Interference Avoidance and Resource Allocation for OFDMA Downlink of Femtocells with Distributed Power Control

OFDMA femtocells in the macrocellular network of which frequency reuse factor is I cause serious interference to macrocell users. while the femtocells improve the performance of indoor users In this letter, a novel downlink resource allocation algorithm for OFDMA femtocell networks is proposed to reduce interference between the macrocells and the femtocells This algorithm allocates femtocell subchannels to avoid interference to macrocell users in the femtocell coverage and minimizes the total transmission power of the femtocell to reduce the negative effect on the performance of the macrocell Simulation results ate provided to present the performance of the proposed algorith

Enhanced response algorithm for spurious TCP timeout(ER-SRTO)

Eifel and F-RTO have been reported representative solutions for spurious TCP timeout. However, these algorithms do not work well in case that delay spike and packet loss occur simultaneously. In this paper, we propose ER-SRTO algorithm which detects the packet loss during delay spike and conducts an efficient recovery in the RTO procedure based on ACK sequence number of retransmission packet. Proposed scheme recovers the lost packet without invoking additional loss recovery procedure. Simulation result shows that proposed algorithm outperforms previous ones

A strategy for industrial waste mitigation—thermal treatment of non-woven polyester fabric debris on ultrahigh-porosity MgO under CO2 atmosphere

Unproperly treated industrial waste creates serious environmental pollution that requires immediate remediation strategies. Non-woven polyester fabrics are widely used in a variety of industrial applications; thus, their debris becomes a major portion of industrial waste. To contribute to advanced industrial waste treatment processes, this study investigated catalytic thermal treatment of non-woven polyester fabric debris on a novel ultrahigh-porosity MgO material under a CO2 environment. The ultrahigh-porosity MgO was synthesized from hydromagnesite via a series of thermal reactions, having a surface area of 208.8 m2 g−1, total pore volume of 0.34 cm3 g−1, and average pore diameter of 2.37 nm. Using the MgO as the catalyst for thermolysis of non-woven polyester fabric debris in CO2 promoted thermal cracking of volatilized species evolved from the non-woven polyester fabric debris thermolysis, thereby increasing the gas product yield and decreasing the liquid product and wax yields. In addition, dehydrogenation and reverse water gas reaction was promoted by the MgO catalyst, leading to more than higher syngas production (up to 16.1 wt% syngas yield) compared to non-catalytic thermolysis (up to 8 wt% syngas yield). The selectivity toward esters was increased, while the selectivities toward benzoic and phthalic acids were decreased, most likely due to the MgO promoting decarboxylation and esterification reactions during the thermolysis. Moreover, the ultrahigh-porosity MgO catalyst was reusable for at least two consecutive cycles. It is hoped that the applicability of the novel material as a catalyst is widened for advanced treatment processes to minimize negative effects of industrial wastes on the environment

Timer and sequence based packet loss detection scheme for efficient selective retransmission in DCCP

Data Congestion Control Protocol (DCCP) is new transport protocol for multimedia applications. Although the standard DCCP does not provide retransmission scheme, many research works have proposed selective retransmission methods for DCCP to improve QoS of applications. However, these researches do not consider packet loss detection scheme although existing packet loss detection schemes are not appropriate for efficient retransmission. This paper proposes a new packet loss detection method for efficient selective retransmission in DCCP. The proposed scheme detects packet loss by using timer and out of sequence packets. Simulation results show that the proposed method improves the performance of retransmission by detecting packet loss more quickly and accurately

TCP-Friendly Retransmission Persistence Management for SR-ARQ Protocols

This letter proposes a new retransmission persistence management scheme for selective repeat automatic repeat request (SR-ARQ) By considering the overall traffic load that has to be managed by SR-ARQ, the proposed scheme arbitrates the retransmission persistence to prevent an abrupt delay increment due to excessive link-level local retransmissions. OPNET simulations show that SR-ARQ performs better with the proposed scheme than with a fixed value of retransmission persistence in terms of the throughput of transmission control protocol (TCP)