DD Process Research Articles

Leveraging an innovative process integration using highly acid-immune blend membranes for enhanced acid recovery and selective salt separation

We investigate the efficiency and advantage of the integrated diffusion dialysis-electrodialysis (DD-ED) system over the DD process for acid recovery with highly acidic wastewater. The investigation uses various acid (HCl/H2SO4) /salt mixtures encompassing iron, copper and aluminium salts (FeCl2, CuCl2, AlCl3, and FeSO4) as simulated feed. The membrane is prepared using blend mixture of polyvinylidene fluoride (PVDF) and polymethyl methacrylate-co-poly chloromethyl styrene copolymer (PMMA-co-PCMSt) solution by non-solvent induced phase inversion on a nonwoven fabric followed by treatment with different tertiary amines. Representative AEM-Q3 membrane prepared by the post modification of blend membrane with a mixture of N, N, N’, N’- tetramethyl diamino hexane (TMDAH) and trimethyl amine (TMA) (1: 1 w/w %) exhibited the best-balanced performance. The membrane recovered a 84.2% AR (%) of acid with 96.28% purity (%) at a flux (JH+) of 7.08 × 10-4 mol cm-2 h-1 from 3 M HCl and 0.2M FeCl2 mixture making it suitable for further studies. A comprehensive comparative study drawn between the DD and integrated DD-ED showed that there was a 2.3 fold increment in acid recovery for the integrated process over the DD process (for the HCl-FeCl2 system). The membranes have also shown good monovalent (Cl-) and bivalent (SO42-) anion selectivity of 7.8. However, the selectivity was further improved to 12.28 by modification of AEM-Q3 membrane, which is double side cast (referred as AEM-Q3/b). The synthetic strategy of the membrane is easy and scalable and has potential for both acid recovery and selective salt separation by ED process.

The genetic landscape of antibiotic sensitivity in Staphylococcus aureus.

Despite the critical importance of essential genes, systems-level investigations of their contribution to antibiotic sensitivity have been limited. Using CRISPR Adaptation-mediated Library Manufacturing (CALM), we generated ultra-dense CRISPR interference (CRISPRi) libraries in methicillin-sensitive and -resistant strains of Staphylococcus aureus, which allowed us to quantify gene fitness on a global scale across ten clinically relevant antibiotics. This led to the identification of a comprehensive set of known and novel biological processes modulating bacterial fitness in the antibiotics. Notably, we found that essential genes from diverse processes dominated antibiotic-gene interactions, including a large number of synergistic interactions between bactericidal antibiotics and processes such as cell wall synthesis/cell division (CC), DNA replication/DNA recombination (DD), protein export, and coenzyme A biosynthesis. Simultaneous genetic perturbations of diverse CC and DD processes aggravated bacterial fitness, revealing a widespread synergy between the two highly coordinated processes. In contrast, perturbation of transcriptional, translational, and select energy processes antagonized the effects of bactericidal antibiotics. Finally, we show that small molecule inhibitors recapitulated synergistic antibiotic-gene interactions, providing a rational foundation for developing novel combinatorial antimicrobial therapies.

Microbial mechanism of biochar addition to reduce N2O emissions from soilless substrate systems

The soilless peat-based substrate partially solves the global soil problem in greenhouse vegetable production. However, it still produces serious N2O emissions due to the application of nutrient solutions. The pyrolysis biochar is regarded as an effective measure to reduce soil N2O emissions. However, the effect and mechanism of biochar on N2O emissions from the soilless substrate remain unknown. Therefore, this study set up six treatments by adjusting the ratio of biochar addition of peat-based substrate: 0% (0BC), 2% (2BC), 4% (4BC), 6% (6BC), 8% (8BC) and 10% (10BC) (v/v). The results showed that compared to the control treatment, N2O emissions reduced by 81%, 71%, 51%, 61%, and 75% in the 2BC, 4BC, 6BC, 8BC and 10BC treatments, respectively. In addition, lettuce yield increased by 10% and 7% in the 2BC and 4BC treatments and decreased by 0.5%, 4% and 6% in the 6BC, 8BC and 10BC treatments, respectively. Combining stable isotope technology, qPCR analysis and high-throughput sequencing, five microbial pathways of N2O production, including bacterial and archaea nitrification (BN and AN), denitrification performed by fungi, denitrifier bacteria and nitrifier bacteria (FD, DD and ND), were roughly distinguished. In addition, the extent of N2O reduction was obtained by δ18O vs.δ15NSP map. For all treatments, overall, the DD process (over 50%) was the main process of N2O production and reduction, while ND and AN processes were almost negligible (less 5%). In detail, the decrease of N2O emissions was caused by decreasing the contribution of FD in the 6BC, 8BC and 10BC treatments and reducing the contribution of BN in the 0BC and 2BC treatments. In addition, biochar addition increased the extent of N2O reduction to N2. In summary, the 2% biochar addition presented the greatest extent of N2O reduction to N2 (83%) and the lowest N2O emissions as well as the highest lettuce yields and nitrogen utilization efficiency. Therefore, 2% biochar is deemed the most optimal addition to the peat-based substrate.

Graphene Oxide/Polyethyleneimine-Modified Cation Exchange Membrane for Efficient Selective Recovery of Ammonia Nitrogen from Wastewater.

Competition for the migration of interfering cations limits the scale-up and implementation of the Donnan dialysis process for the recovery of ammonia nitrogen (NH4+-N) from wastewater in practice. Highly efficient selective permeation of NH4+ through a cation exchange membrane (CEM) is expected to be modulated via tuning the surface charge and structure of CEM. In this work, a novel CEM was designed to form a graphene oxide (GO)-polyethyleneimine (PEI) cross-linked layer by introducing self-assembling layers of GO and PEI on the surface of a commercial CEM, which rationally regulates the surface charge and structure of the membrane. The resulting positively charged membrane surface exhibits stronger repulsion for divalent cations compared to monovalent cations according to Coulomb's law, while, simultaneously, GO forms π-metal cation conjugates between metal cations (e.g., Mg2+ and Ca2+), thus limiting metal cation transport across the membrane. During the DD process, higher NH4+ concentrations resulted in a longer time to reach Donnan equilibrium and higher NH4+ flux, while increased Mg2+ concentrations resulted in lower NH4+ flux (from 0.414 to 0.213 mol·m-2·h-1). Using the synergistic effect of electrostatic interaction and non-covalent cross-linking, the designed membrane, referred to as GO-PEI (20) and prepared by a 20 min impregnation in the GO-PEI mixture, exhibited an NH4+ transport rate of 0.429 mol·m-2·h-1 and a Mg2+ transport rate of 0.003 mol·m-2·h-1 in single-salt solution tests and an NH4+/Mg2+ selectivity of 15.46, outperforming those of the unmodified and PEI membranes (1.30 and 5.74, respectively). In mixed salt solution tests, the GO-PEI (20) membrane showed a selectivity of 15.46 (~1.36, the unmodified membrane) for NH4+/Mg2+ and a good structural stability after 72 h of continuous operation. Therefore, this facile surface charge modulation approach provides a promising avenue for achieving efficient NH4+-selective separation by modified CEMs.

Decision-Making Under Risk and Uncertainty by Substance Abusers and Healthy Controls.

Cognitive impairment characterized by high impulsivity and risk-taking has been correlated with substance-related disorders. However, it is unclear if the decision-making process is well known upon consideration of factors such as uncertainty environments, risk, and time manipulation in different decision-making procedures. The main objective of this study was to identify behavioral differences between substance abusers and healthy control participants in a behavioral test battery, including (1) two uncertainty decision-making tasks, the Balloon Analog Risk Task (BART) and the Iowa Gambling Task (IGT, trial 1–40); (2) three risk-taking tasks, the Columbia Card Task Hot version (CCT-hot), Columbia Card Task Cold version (CCT-cold), and the IGT (trial 41–100); and (3) an impulsivity task, the Delay Discounting task (DD). The second objective looked at how the six behavioral tests correlate. We worked with a sample of 54 adult participants (Substance abusers: n = 28; Healthy controls: n = 26). An anonymous survey website was created to execute all the cognitive tasks. The results showed no statistically significant differences between the groups in any of the tasks. However, the results showed an upward trend of impulsive (i.e., steeply discounting curve) and risk-taking behaviors (i.e., a low learning curve in IGT) in substance abuse participants. The factor analysis results showed four different main factors: (1) risk-taking task in the IGT (trial 40–100), (2) uncertainty task in BART, (3) impulsivity in DD, IGT (trial 1–40), and (4) deliberate process in the Columbia card task (cold and hot). We conclude that factors such as the uncertainty tasks in the BART and the first block of IGT trials, the risk cues in the CCT tasks (i.e., number of loss, number of gains, and loss cards), and the time to delivery in the DD task, can affect the complex decision-making process in both clinical and healthy groups.

Investigation of key process parameters in acid recovery for diffusion dialysis using novel (MDMH-QPPO) anion exchange membranes

Investigating the influence of operating parameters is a critical step in development of diffusion dialysis for acid recovery. A series of novel anion exchange membranes consisted of methyl 6-(dimethylamino) hexanoate (MDMH) and poly (2, 5-dimethylphenyl oxide) are successfully fabricated and used for acid recovery via DD process. Initially, the 6-(dimethylamino) hexanoic acid and MDMH are synthesized via condensation reaction and its chemical structure is confirmed by 1H NMR spectroscopy. After membranes fabrication, the chemical composition and morphological structures are confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy. The MDMH-QPPO AEMs possess good acid permeability, selectivity, and outstanding thermo-mechanical stability. A synthesized membrane (MDMH-QPPO-5) with better performance of acid permeability and selectivity is selected for mathematical and statistical studies of process parameters in diffusion dialysis. The effect of process parameters including temperature, time and feed concentration are studied through full factorial design (FFD). The half normal plot is used to investigate the order of process parameters that considerably affecting the acid dialysis coefficient and separation factor. The results showed that the investigation of significant process parameters is useful to improve the acid recovery via diffusion dialysis.

Augmenting acid recovery from different systems by novel Q-DAN anion exchange membranes via diffusion dialysis

Abstract In this study, a series of novel anion exchange membranes composed of polyvinyl alcohol (PVA) and various amount of synthesized anion exchange precursor were successfully prepared and used for acid recovery by DD process. The anion exchange precursor (Q-DAN) was synthesized through reaction of 1,5-diaminonaphthalene (DAN) and 2,3-epoxypropyltrimethylammonium chloride (EPTC) which was confirmed by proton NMR. The dosage of Q-DAN inside membrane matrix played an important role to determine the electrochemical and physicochemical properties of Q-DAN AEMs. Influences of Q-DAN and multivalent metal ions on acid recovery were elaborated in detail. Acid dialysis coefficients (UH) values for FeCl2-HCl system were in the range of 0.0194–0.0295 m/h and separation factors were ranged from 27.84 to 52.60 at 25 °C. Furthermore, acid dialysis coefficient (3.28 times) and separation factor (2.84 times) were much greater than commercial membrane DF-120 (UH and S = 0.009 m/h and 18.5), respectively. Moreover, Q-DAN-4 membrane was selected to investigate the effects of multivalent metal ions on diffusion dialysis. The results showed that the presence of different metal salts in hydrochloric acid solution effect the membrane diffusivity and selectivity in diffusion dialysis process due to complexation of metal ions and acid.

Dipolar dissociation dynamics in electron collisions with carbon monoxide

SynopsisDipolar dissociation (DD) dynamics of carbon monoxide with electron collision has been studied using velocity slice imaging (VSI) technique. Threshold of the process has been obtained from the ion yield curve. Using the time sliced images kinetic energy and angular distribution have been obtained providing the detailed dynamics involved in the DD process. Two ion-pair states have been identified from the angular distribution measurements.

Nitrate removal from natural water by coupling adsorption and Donnan dialysis

A hybrid adsorption/Donnan dialysis (DD) process for nitrate removal using PUROLITE A520E resin as an adsorbent was investigated in this work. PUROLITE resin was introduced into the DD process due to its good selectivity adsorption for nitrate and widespread availability. This study was conducted in order to benefit from each process, and it was an original and new combination. The retention efficiency of nitrate was discussed by considering the factors of adsorbent mass, nature of the receiver electrolyte and flow rate. The coupling was a solution to improve the resin mass and the amount of nitrate removed. The coupling was successfully performed, with a nitrate removal capacity of about 7 mg/g.

Optimization of Cu/Low-k Dual Damascene Post-Etch Residue and TiN Hard Mask Removal

For advanced technology nodes TiN hard mask integration into Cu/low-k via/trench DD process requires the mask to be fully stripped after DD etching. The one-step H2O2 containing wet chemical clean aiming to removing TiN mask often failed to simultaneously clean etch residue. We developed more reliable two-step wet chemical process combining a solvent-based post-etch residue clean followed by a solvent/H2O2 mixture strip for TiN mask removal. Bath lifetime optimization was also demonstrated.

Novelties Within the Framework for Information System Due Diligence

ABSTRACTThe information system (IS) field lacks a scientifically based analytical tool for rapid delivery of IS due diligence. In 2013, a framework for IS due diligence (FISDD) was published. The work on this framework was continued with proceeding development and evaluation. One of the most important objectives of today’s business is making savings concerning various resources. The main novelty of the upgraded framework is the replacement of some of the manually conducted questionnaires with web-based questionnaires. This novelty reduces the total time required for on-site ISDD activities by 35–50%, as has been the result of several real cases. The results demonstrate and confirm the usefulness of upgrading FISDD, which increases its efficiency in DD processes, which is the main contribution of this article.

Effect of novel polysiloxane functionalized poly(AMPS-co-CEA) membranes for base recovery from alkaline waste solutions via diffusion dialysis

The corresponding poly(AMPS-co-CEA) based membrane which showed high base permeability and proper separation factor in alkali recovery via DD process.

LRK-1, a C. elegans PARK8-Related Kinase, Regulates Axonal-Dendritic Polarity of SV Proteins

Neurons are polarized cells that contain distinct sets of proteins in their axons and dendrites. Synaptic vesicles (SV) and many SV proteins are exclusively localized in the presynaptic regions but not in dendrites. Despite their fundamental importance, the mechanisms underlying the polarized localization of SV proteins remain unclear. The transparent nematode Caenorhabditis elegans can be used to examine sorting and transport of SV proteins in vivo. Here, we identify a novel protein kinase LRK-1, a C. elegans homolog of the familial Parkinsonism gene PARK8/LRRK2 that is required for polarized localization of SV proteins. In lrk-1 deletion mutants, SV proteins are localized to both presynaptic and dendritic endings in neurons. This aberrant localization of SV proteins in the dendrites is dependent on the AP-1 mu1 clathrin adaptor UNC-101, which is involved in polarized dendritic transport, but not on UNC-104 kinesin, which is required for the transport of SV to presynaptic regions. The LRK-1 proteins are localized in the Golgi apparatus. These results suggest that the LRK-1 protein kinase determines polarized sorting of SV proteins to the axons by excluding SV proteins from the dendrite-specific transport machinery in the Golgi.

Feasibility study of model-independent approach to φ3 measurement using Dalitz plot analysis

In this paper, we present results of a feasibility study of a model-independent way to measure the angle φ3 of the unitarity triangle. The method involves B±→DK± decays where the neutral D decays to the K0 Sπ+π- final state, together with the sample of decays of CP-tagged D mesons (produced, e.g. in ψ(3770)→DD process) to the same final state. We consider different approaches to the extraction of φ3 and obtain the expected statistical accuracy of the φ3 measurement as a function of B and DCP statistics.