Response of BVOC emissions from Fraxinus excelsior to biotic stress

C

Seebeck coefficient of thermopile made of nickel-coated carbon fiber

A textile-based thermopile has been fabricated by etching the nickel layer of a nickel coated carbon fiber (NiCF) selectively to form a series of CF-NiCF junctions along the NiCF. The pristine NiCF was inserted into the polyester woven fabric manually. Each half part of the float yarns was covered with Lurapret® D579 dropwise to form a 36-pair CF-NiCF thermopile. After drying in the oven, the sample was etched in the etching solution, then rinsed with water and air dried. The Seebeck coefficient resulting from 36-pair CF-NiCF thermopile is 93.04 µV/K. This proofs that creating a flexible thermoelectric generator from a conductive textile yarn is possible

Effect of surfactant addition on the biofiltration of siloxane-contaminated gas streams

Biogas contains low levels of volatile methyl siloxanes (VMS), which are responsible for severe damage to turbines or internal combustion engines during energy recovery. In this study, we investigated the removal of the linear octamethyltrisiloxane (L3) and cyclic octamethylcyclotetrasiloxane (D4) from gas by using two biofilters (BFs) filled with either woodchips and compost (WC) or perlite (PER). To overcome the mass transfer limitation, the addition of a synthetic (Tween 80) and a biological (Quillaja saponin, QS) surfactant on the removal of VMS in both BFs was studied. Tween 80 (added at × 1 critical micelle concentration, CMC) and QS (also at × 1 CMC) enhanced VMS removal in both BFs. Specifically, the performance of both BFs increased from an average VMS elimination capacity (EC) of 0.07 ± 0.04 g VMS m−3 h−1 to 0.24 ± 0.08 g VMS m−3 h−1 (Tween 80) and 0.43 ± 0.02 g VMS m−3 h−1 (QS). However, higher concentrations of Tween 80 ( × 3 CMC) did not further improve VMS removal. The WC BF exhibited a higher maximum EC of 0.63 g VMS m−3 h−1 (0.37 g D4 m−3 h−1 and 0.26 g L3 m−3 h−1), with a VMS RE of 28.4 ± 2.0% (D4 RE = 30.4% and L3 RE = 26.5%). The PER BF obtained a maximum EC of 0.52 g VMS m−3 h−1 (0.28 g D4 m−3 h−1 and 0.23 g L3 m−3 h−1), along with a VMS RE of 32.0 ± 0.8% (D4 RE = 31.2% and L3 RE = 32.8%). The most abundant genera in the WC BF were Mycobacterium (7.5–1.8%), Rhodococcus (1.1–7.2%), and Planctomicrobium (5.1–2.9%). However, given the high microbial diversity present in WC BF and the complex structure of VMS, their removal was most likely due to the joint activity of several microorganisms with VMS-degrading capacity, such as Bacillus (0.58–0.39%), Pseudomonas (0.07–0.04%), Dokdonella (0.50–0.10%), Microbacterium (0.5%), Novosphingobium (0.02%), Gordonia (0.5–0.1%), and Sphingopyxis (0.07%)

Biofiltration of gaseous mixtures of dimethyl sulfide, dimethyl disulfide and dimethyl trisulfide: Effect of operational conditions and microbial analysis

The efficient removal of volatile sulfur compounds (VSCs), such as dimethyl sulfide (DMS), dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS), is crucial due to their foul odor and corrosive potential in sewer systems. Biofilters (BFs) offer promise for VSCs removal, but face challenges related to pH control and changing conditions at full scale. Two BFs, operated under acidophilic conditions for 78 days, were evaluated for their performance at varying inlet concentrations and empty bed residence times (EBRTs). BF1, incorporating 4–6 mm marble limestone for pH control, outperformed BF2, which used NaHCO3 in the nutrient solution. BF1 displayed better resilience, maintained a stable pH of 4.6 ± 0.6, and achieved higher maximum elimination capacities (ECmax, 41 mg DMS m− 3 h− 1 (RE 38.3%), 146 mg DMDS m− 3 h− 1 (RE 83.1%), 47 mg DMTS m− 3 h− 1 (RE 93.1%)) at an EBRT of 56 s compared to BF2 (9 mg DMS m− 3 h− 1 (RE 7.1%), 9 mg DMDS m− 3 h− 1 (RE 4.8%) and 11 mg DMTS m− 3 h− 1 (RE 26.6%)). BF2 exhibited pH stratification and decreased performance after feeding interruptions. The biodegradability of VSCs followed the order DMTS > DMDS > DMS, and several microorganisms were identified contributing to VSCs degradation in BF1, including Bacillus (14%), Mycobacterium (11%), Acidiphilium (7%), and Acidobacterium (3%)

Control dependence for extended finite state machines

Though there has been nearly three decades of work on program slicing, there has been comparatively little work on slicing for state machines. One of the primary challenges that currently presents a barrier to wider application of state machine slicing is the problem of determining control dependence. We survey existing related definitions, introducing a new definition that subsumes one and extends another. We illustrate that by using this new definition our slices respect Weiser slicing’s termination behaviour. We prove results that clarify the relationships between our definition and older ones, following this up with examples to motivate the need for these differences

Effect of toluene on siloxane biodegradation and microbial communities in biofilters

The removal of volatile methyl siloxanes (VMS) from landfill biogas is crucial for clean energy utilization. VMS are usually found together with aromatic compounds in landfill biogas of which toluene is the major representative. In the present study, two biofilters (BFs) packed with either woodchips and compost (WC) or perlite (PER) were used to study the (co–) removal of octamethyltrisiloxane (L3) and octamethylcyclotetrasiloxane (D4) from gas in presence and absence of toluene, used as a representative aromatic compound. The presence of low inlet toluene concentrations (315 ±19 – 635 ±80 mg toluene m-3) enhanced the VMS elimination capacity (EC) in both BFs by a factor of 1.8 to 12.6. The highest removal efficiencies for D4 (57.1 ±1.1 %; EC =0.12 ±0.01 gD4 m-3 h-1) and L3 (52.0 ±0.6 %; EC =0.23 ±0.01 gL3 m-3 h-1) were observed in the BF packed with WC. The first section of the BFs (EBRT =9 min), where toluene was (almost) completely removed, accounted for the majority (87.7 ±0.6 %) of the total VMS removal. Microbial analysis revealed the impact of VMS and toluene in the activated sludge, showing a clear selection for certain genera in samples influenced by VMS in the presence (X2) or absence (X1) of toluene, such as Pseudomonas (X1 =0.91 and X2 =12.0 %), Sphingobium (X1 =0.09 and X2 =4.04 %), Rhodococcus (X1 =0.42 and X2 =3.91 %), and Bacillus (X1 =7.15 and X2 =3.84 %). The significant maximum EC values obtained by the BFs (0.58 gVMS m-3 h-1) hold notable significance in a combined system framework as they could enhance the longevity of traditional physicochemical methods to remove VMS like activated carbon in diverse environmental scenarios