Physical Partition Research Articles

Biochar for volatile organic compound (VOC) removal: Sorption performance and governing mechanisms

Sorption is one of the most efficient and low cost strategies for volatile organic compound (VOC) removal, but VOC sorption by biochar has seen limited research. In this work, gas phase sorption experiments were conducted to determine the sorption potential and mechanisms of VOCs onto biochar. A total of 15 biochars produced from 5 common feedstocks at 300, 450, and 600°C were evaluated as sorbents. Three common VOCs (acetone, cyclohexane, and toluene) were chosen as sorbates. The results showed that all the tested biochars had VOC sorption capacity in the range of 5.58–91.2mgg−1. The sorption capacities were mainly influenced by both the surface area of biochar and its noncarbonized organic matter content. The vapor sorption process was exothermic, and the removal of VOCs by the biochars decreased with increasing feedstock temperature. Both the physical adsorption and partition mechanisms played important roles in controlling the VOC removal by the biochars. Biochar maintained its VOC removal ability after five consecutive sorption-desorption cycles, which indicated good reusability. Findings of this work suggest that biochar is a promising alternative sorbent for gaseous VOC removal.

Construction and application of a model on the resolution of tropic acid enantiomers by enantioselective liquid-liquid extraction in centrifugal contactor separators

Abstract This paper reports on the construction and application of a mathematical model on multistage liquid-liquid extraction of tropic acid (TA) enantiomers in centrifugal contactor separators (CCSs). An efficient extraction system was obtained, where HE-β-CD and butyl acetate was selected as the best extractant and organic solvent. The mechanism of reactive extraction of TA enantiomers by HE-β-CD was proposed and the thermodynamic constants such as physical partition coefficient and reactive equilibrium constants were obtained, which combined with the law of mass conservation gave the basis for construction of the model. The model was applied to predict and optimize the symmetrical separation of TA enantiomers. The optimal condition was obtained as follows, O/W volume ratio of 3.0, pH of 3.00 and HE-β-CD concentration of 0.05 mol/L, where ee eq (equal enantiomeric excess) can reach up to 42%. The simulated results reveal that the minimum number of stages for ee eq > 97% and ee eq > 99% was 56 and 78, respectively.

Chiral ligand exchange countercurrent chromatography: Equilibrium model study on enantioseparation of mandelic acid

The equilibrium model in enantioseparation of mandelic acid by chiral ligand exchange countercurrent chromatography was investigated using N-n-dodecyl-l-proline as chiral ligand and cupric ion as central metal. Important parameters, including physical partition coefficient and formation constants of binary and ternary coordination complexes in the two-phase solvent system, were determined. This equilibrium model could give an excellent prediction of distribution ratio and enantioseparation factor of the analyte in the biphasic solvent system, which was further verified by experiments. All the average relative deviations were less than 12%, indicating that the established model could provide a simple computational approach for optimization of enantioseparation conditions in chiral ligand exchange countercurrent chromatography.

Fighting For Ireland: The Creation of Northern and Southern Irish National Identity during the First World War

The decade of 1912-1923 in Ireland was a period of transition, change, and bloodshed. By the end of the period Ireland had gone from a British colony to two separate nations, the Irish Free State and Northern Ireland. While the actions of radical ultra-nationalists and unionists insured this physical partition of Ireland, the psychological and cultural divide that dominates Irish society was also created during this period. The divide between north and south was created by the epic struggle of the First World War. Both northern and southern Irish attempted to use the war to reinforce their position in the new Ireland that was to be created at the war's conclusion. The results were drastically different for both sides as the south was driven into the arms of the ultranationalists and the north into the radical unionists. By looking at public monuments, widespread stereotypes and cultural works, the separation between northern and southern Ireland becomes obvious as each side interpreted the war on opposite ends of the spectrum. The south, with its republican-nationalist leaders choosing to ignore the war and the soldiers contributions to the creation of the new Irish state to the point where the nation now suffers from a "collective amnesia". In the north, the unionists took their role in the war to become one of the foundation stones in their culture and identity. Such veneration led the unionists to develop a culture of sacrifice and bloodshed, which has contributed to the violence in Northern Ireland.

Virtual partition surface temperature sensor based on linear parametric model

Multi-zone structure is common in commercial office buildings, retail stores and supermarkets. Because there is no physical partition between zones, there could exist significant thermal impact among the adjacent zones than in other commercial buildings. It is critical to accurately analyze the energy interaction and reduce the modeling uncertainty for supporting advanced control. We propose a virtual partition surface temperature sensor for quantifying the variables and solve this challenge by using linear parametric models. The derived models based on physical law can be used as a guideline on selecting appropriate orders in mainly ARMAX (autoregressive moving average with exogenous variables) and/or ARX for improving the sensor’s performance. Validation of the virtual temperature models is conducted by three validation criteria: goodness of fit (G), mean squared error (MSE) and coefficient of determination (R2) under off-control conditions. The validation results show that the physical model based linear parametric model, ARX 211, performs well and similar to other system identification models, such as ARMAX 2111 and ARX 221, for estimating surface temperatures. The sensitivity analysis using three on-control conditions (under-sizing, proper-sizing and over-sizing condition) is conducted for analyzing and evaluating the performance and barriers of this virtual sensor. The proposed easy-to-implement model can be applied to support supervisory control of equipment in multi-zone buildings and other applications to supplement the measurements, like estimating the temperature of a structure integrated cooling or heating application in renewable energy areas.

Topological field theory of dynamical systems. II

This paper is a continuation of the study [Chaos.22.033134] of the relation between the stochastic dynamical systems (DS) and the Witten-type topological field theories (TFT). Here, it is discussed that the stochastic expectation values of a DS must be complemented on the TFT side by (-1)(F^), where F^ is the ghost number operator. The role of this inclusion is to unfold the natural path-integral representation of the TFT, i.e., the Witten index that equals up to a topological constant to the partition function of the stochastic noise, into the physical partition function of TFT/DS. It is also shown that on the DS side, the TFT's wavefunctions are the conditional probability densities.

Bioaerosol deposition in single and two-bed hospital rooms: A numerical and experimental study

Aerial dispersion of pathogenic microorganisms and subsequent contamination of surfaces is well recognised as a potential transmission route for hospital acquired infection. Simulation approaches such as computational fluid dynamics (CFD) are increasingly used to model particle behaviour in indoor air and the results interpreted to infer infection risk. However there is little validation of such methods in the open literature. This paper considers the ability of CFD simulations to accurately predict spatial distributions of bioaerosol deposition in indoor environments and explores the influence that different room layouts have on deposition patterns. Spatial deposition of aerosolised Staphylococcus aureus was measured in an aerobiology test room arranged in three different layouts: an empty room, a single-bed and a two-bed hospital room. Comparison with CFD simulations using Lagrangian particle tracking demonstrates that a realistic prediction of spatial deposition is feasible, and that a Reynolds Stress (RSM) turbulence model yields significantly better results than the k–ɛ RNG turbulence model used in most indoor air simulations. Results for all layouts demonstrate that small particle bioaerosols are deposited throughout a room with no clear correlation between relative surface concentration and distance from the source. However, a physical partition separating patients is shown to be effective at reducing cross-contamination of neighbouring patient zones.

New developments in pervasive and ambient information systems

This special issue contains selected papers from the 2nd International Conference on Ambient Systems, Networks and Technologies (ANT 2011), which was held at Niagara Falls, Ontario, Canada, September 19–21, 2011. The conference attracted a large number of scientific papers that contributed to the state-of-the-art in the areas to the theme of the conference. All the papers selected for this special issue were subjected to a two rounds of rigorous review process. Based on the reviewers’ feedback, a total of seven papers were selected for publication from ten invited papers. The accepted papers cover interesting works on new developments in pervasive and ambient systems such as smart environments, environmental monitoring, information search and processing, and the practical use of smart devices in industrial applications. A brief summary is as follows. Identifying and recognizing objects in (indoor) smart environment is one of the challenging research areas in pervasive and ambient systems. The paper by Menon et al. proposes a novel model for identifying and tracking objects in smart environments. This work integrates recognition and spatio-temporal reasoning in order to achieve improved precision in smart environments. The proposed approach is evaluated through experimentation in terms of face recognition, which shows improved performance, precision, and recall. Wireless sensor network (WSN) augmented with ambient intelligence has interesting applications in home living. Rawi et al. in their paper develop WSN-based Human Comfort Ambient Intelligence system, which exploits fuzzy rules in order to measure human comfort index in a living space. It explores complex relationship among multiple comfort factors such as thermal, visual, and indoor air comfort factors. Further, the system is developed in a way such that it provides flexibility in terms of adding or removing comfort factors as well as sensor nodes. Trust is another important issue in providing truly smart environments in living spaces. El Husseini et al. propose a trust model that takes into account user’s past and present behavior. The proposed model utilizes a lightweight authentication key agreement protocol in order to ensure trust and to provide mutual authentication between communicating entities. The model is developed such that it optimizes the communication and processing of resource scare devices in smart environments. Al-Turjman et al. explore the utilization of WSN in environmental monitoring applications such as forestry. The large number of failures complicates the process of environmental monitoring as WSNs often suffer from physical damages and network partition. This paper proposes 3D grid-based deployment for relay nodes and is based on a minimum spanning tree construction. It is used in re-connecting the disjointed WSN sectors and has the potential to optimize various factors including: average relay node count and distribution, the scalability of the federated WSNs in large-scale applications, and the robustness of the topologies. Effective processing of queries in mobile ad hoc network is crucial in order to optimize performance, reduce energy consumption, and avoid failures. Nghiem et al. E. Shakshuki (&) Jodrey School of Computer Science, Acadia University, Wolfville, NS, Canada e-mail: elhadi.shakshuki@acadiau.ca

Module partition process model and method of integrated service product

Due to customers’ constantly increasing demand for personalized products and services, manufacturing enterprises must provide more diverse physical products and services in the product sale stage. However, the massive diversity of personalized products and services offered leads to the internal diversification of products and services, which greatly increases production costs. The application of the modular method can effectively improve the reusability of a product or service, and reduce internal diversification of the product and service. In this paper, the interactive modular design process is established by the analysis of the relationship between a product or service of integrated service product (ISP) and the analysis of the physical module and service module. This paper deals with the module partition principle of ISP, puts forward the three-stages module partition processes and methods, mainly including service module partition processes based on the “Top-Down” and “Bottom-Up” methods, the physical module partition process based on the “Top-Down”, and the module partition methods based on Quality Function Deployment and mapping matrix. Finally, a case study is done on an electric power transformer using proposed principle and methods, and the processes and methods can achieve the interactive module partition of ISP.

Study on Modular Design Method for CNC Lathe

A multi-dimensional module partition methodology is put forward for CNC lathe, in which not only the functional module partition and the physical structure module partition of CNC machine tools are taken into account, but the characteristics of different stages of in the whole life-cycle of machine tools is considered as well. On the basis of this the principle of module partition for CNC machine tools are presented. The mechanical structure system of CNC lathe is elaborated on the functional module and structural module. A CNC machine tool company’s HTC Series CNC lathes modular design is illustrated as an example.

Improvement of the Indoor Environment and Airborne Contamination Control in an Operating Room

Modern operating rooms are increasingly turning to contamination control by ventilating technology for the infectious control. The objective of this study is to present the strategic approach on performance improvement of the ventilating system for a hospital operating room under limit budget. A physical partition curtain has been proposed and conducted around the high efficiency particulate air (HEPA) filter of an operating room to validate the improvement of air distribution and contamination control. Numerical simulation of a full-scale operating room has been carried out at a district hospital. The results from computer simulation revealed that the improvement of airflow could be achieved satisfactorily by the application of a physical partition curtain at the length of 1.2 m. Ventilation performance could be assessed extensively not only by airflow distribution and concentration profile but also by the calculation of contamination concentration decay.

Quantum Riemann surfaces in Chern-Simons theory

We construct from first principles the operators $\hat A_M$ that annihilate the partition functions (or wavefunctions) of three-dimensional Chern-Simons theory with gauge groups $SU(2)$, $SL(2,\mathbb{R})$, or $SL(2,\mathbb{C})$ on knot complements $M$. The operator $\hat A_M$ is a quantization of a knot complement's classical $A$-polynomial $A_M(\ell,m)$. The construction proceeds by decomposing three-manifolds into ideal tetrahedra, and invoking a new, more global understanding of in topological quantum field theory to put them back together. We advocate in particular that, properly interpreted, gluing $=$ symplectic reduction. We also arrive at a new finite-dimensional state integral model for computing the analytically continued holomorphic blocks that compose any physical Chern-Simons partition function.

A soil bacterium regulates plant acquisition of iron via deficiency‐inducible mechanisms

Despite the abundance of iron in nature, it is the third most limiting nutrient for plants due to its minimal solubility in most soils. While certain soil microbes produce chelating agents that enhance the solubility of iron, the effectiveness of such siderophores in the assimilation of iron by plants is debated. With an increasing understanding that select soil microbes play a signaling role in activating growth and stress responses in plants, the question arises as to whether such symbionts regulate iron assimilation. Here we report a previously unidentified mechanism in which the growth-promoting bacterium Bacillus subtilis GB03 activates the plant's own iron acquisition machinery to increase assimilation of metal ions in Arabidopsis. Mechanistic studies reveal that GB03 transcriptionally up-regulates the Fe-deficiency-induced transcription factor 1 (FIT1), which is necessary for GB03-induction of ferric reductase FRO2 and the iron transporter IRT1. In addition, GB03 causes acidification of the rhizosphere by enhancing root proton release and by direct bacterial acidification, thereby facilitating iron mobility. As a result, GB03-exposed plants have elevated endogenous iron levels as well as increased photosynthetic capacity compared with water-treated controls. In contrast, loss-of-function fit1-2 mutants are compromised in terms of enhanced iron assimilation and photosynthetic efficiency triggered by GB03. In all studies reported herein, a physical partition separating roots from bacterial media precludes non-volatile microbial siderophores from contributing to GB03-stimulated iron acquisition. These results demonstrate the potential of microbes to control iron acquisition in plants and emphasize the sophisticated integration of microbial signaling in photosynthetic regulation.

Soil Bacteria Elevate Essential Oil Accumulation and Emissions in Sweet Basil

Plant growth-promoting rhizobacteria ameliorate environmental conditions for plants by facilitating nutrient uptake and mitigating disease susceptibility. While volatile chemicals from certain soil microbes are sufficient to elicit growth and defense responses in Arabidopsis, whether such volatile signals can induce essential oil accumulation and chemical emissions has yet to be reported. Here, we provide biochemical evidence that the plant growth-promoting soil bacterium Bacillus subtilis GB03 releases volatile chemicals that elevate fresh weight essential oil accumulation and emissions along with plant size in the terpene-rich herb sweet basil (Ocimum basilicum). The two major essential oil components from sweet basil, alpha-terpineol and eugenol, increased ca. 2- and 10-fold, respectively, in plants exposed to GB03 volatiles or with root inoculation as compared to water controls. On a fresh and dry weight basis, shoot and root biomass increases of ca. 2-fold were observed with GB03 volatile exposure or GB03 media inoculation as compared with controls. In testing the efficacy of GB03 volatiles to trigger plant growth and secondary compound production, a physical partition separating roots from bacterial media was provided to preclude nonvolatile microbial elicitors from contributing to GB03-stimulated basil responses. These results demonstrate that volatile bacterial elicitors can concomitantly increase essential oil production and biomass in an herbaceous species rich in commercially valued essential oils.

Pond attributes influence competitive interactions between tadpoles and mosquito larvae

Abstract Tadpoles and mosquito larvae often coexist in natural freshwater bodies. We studied competitive interactions between: (i) tadpoles of the striped marsh frog (Limnodynastes peronii) and larvae of the mosquito Culex quinquefasciatus; and (ii) tadpoles of the common eastern froglet (Crinia signifera) and larvae of the mosquito Aedes australis. These two sets of taxa occur in natural water bodies in the Sydney region. Laboratory trials revealed competition between mosquito larvae and tadpoles in both systems. For example, mosquitoes displayed reduced rates of survival, growth and development, and smaller size at metamorphosis, when they were raised with tadpoles. The intensity of competitive suppression was influenced by attributes such as pond size (and hence, larval density), the location of food (on the water surface vs the substrate), and the extent of opportunities for direct physical interactions between the two competing organisms. These effects differed between the two study systems, suggesting that the mechanisms of suppression also differed. Limnodynastes peronii tadpoles suppressed C. quinquefasciatus even when the two types of organisms were separated by a physical partition, suggesting that chemical or microbiological cues may be responsible. Pond attributes also affected the impact of C. signifera tadpoles on Aedes larvae, but (unlike the Limnodynastes–Culex system) these effects disappeared when densities were lowered or when the tadpoles and mosquito larvae were physically separated. Thus, direct physical interactions may suppress mosquitoes in the Crinia–Aedes system. Our results suggest that tadpoles suppress the viability of larval mosquitoes by multiple pathways.

Microfluidic culture platform for neuroscience research

This protocol describes the fabrication and use of a microfluidic device to culture central nervous system (CNS) and peripheral nervous system neurons for neuroscience applications. This method uses replica-molded transparent polymer parts to create miniature multi-compartment cell culture platforms. The compartments are made of tiny channels with dimensions of tens to hundreds of micrometers that are large enough to culture a few thousand cells in well-controlled microenvironments. The compartments for axon and somata are separated by a physical partition that has a number of embedded micrometer-sized grooves. After 3-4 days in vitro (DIV), cells that are plated into the somal compartment have axons that extend across the barrier through the microgrooves. The culture platform is compatible with microscopy methods such as phase contrast, differential interference microscopy, fluorescence and confocal microscopy. Cells can be cultured for 2-3 weeks within the device, after which they can be fixed and stained for immunocytochemistry. Axonal and somal compartments can be maintained fluidically isolated from each other by using a small hydrostatic pressure difference; this feature can be used to localize soluble insults to one compartment for up to 20 h after each medium change. Fluidic isolation enables collection of pure axonal fraction and biochemical analysis by PCR. The microfluidic device provides a highly adaptable platform for neuroscience research and may find applications in modeling CNS injury and neurodegeneration. This protocol can be completed in 1-2 days.

Pond attributes influence competitive interactions between tadpoles and mosquito larvae

Abstract Tadpoles and mosquito larvae often coexist in natural freshwater bodies. We studied competitive interactions between: (i) tadpoles of the striped marsh frog (Limnodynastes peronii) and larvae of the mosquito Culex quinquefasciatus; and (ii) tadpoles of the common eastern froglet (Crinia signifera) and larvae of the mosquito Aedes australis. These two sets of taxa occur in natural water bodies in the Sydney region. Laboratory trials revealed competition between mosquito larvae and tadpoles in both systems. For example, mosquitoes displayed reduced rates of survival, growth and development, and smaller size at metamorphosis, when they were raised with tadpoles. The intensity of competitive suppression was influenced by attributes such as pond size (and hence, larval density), the location of food (on the water surface vs the substrate), and the extent of opportunities for direct physical interactions between the two competing organisms. These effects differed between the two study systems, suggesting that the mechanisms of suppression also differed. Limnodynastes peronii tadpoles suppressed C. quinquefasciatus even when the two types of organisms were separated by a physical partition, suggesting that chemical or microbiological cues may be responsible. Pond attributes also affected the impact of C. signifera tadpoles on Aedes larvae, but (unlike the Limnodynastes–Culex system) these effects disappeared when densities were lowered or when the tadpoles and mosquito larvae were physically separated. Thus, direct physical interactions may suppress mosquitoes in the Crinia–Aedes system. Our results suggest that tadpoles suppress the viability of larval mosquitoes by multiple pathways.

A Case Study of Logistic QSAR Modeling Methods and Robustness Tests

Acute toxicity (15-min EC50) determination of 16 substituted naphthalene compounds to Photobacterium phosphoreum was undertaken according to the standard procedures, while the effects of molecular structures of selected compounds on their toxicity to test microorganisms were logistically conducted using the quantitative structure–activity relationship (QSAR) technique. The relationship was developed as −log EC50=5.5916 (±0.1189)−7.4893(±0.4900)qH++0.7771(±0.0619Elumo+0.0088(±0.0009)α(N=16, R2adj=0.9698, SE=0.0892, P=0.0000). The cluster analyses of individual structure descriptors as well as the quality control chart and Monte Carlo simulation test indicated that the prediction model was reasonable and robust even if tested with several different methods. Furthermore, the quantum chemical parameters entering into the QSAR model were used to discuss the possible toxicity pathways, and the results revealed that the selected compounds were reactive and their toxicity behaviors were complex processes containing physical partition stages as well as biochemical reaction stages.

On the Distribution of Eigenvalues of Grand Canonical Density Matrices

Using physical arguments and partition theoretic methods, we demonstrate under general conditions, that the eigenvalues w(m) of the grand canonical density matrix decay rapidly with their index m, like w(m)∼exp[−βB−1(ln m)1+1/α], where B and α are positive constants, O(1), which may be computed from the spectrum of the Hamiltonian. We compute values of B and α for several physical models, and confirm our theoretical predictions with numerical experiments. Our results have implications in a variety of questions, including the behaviour of fluctuations in ensembles, and the convergence of numerical density matrix renormalization group techniques.

The Ising Partition Function for 2D Grids with Periodic Boundary: Computation and Analysis

The Ising partition function for a graph counts the number of bipartitions of the vertices with given sizes, with a given size of the induced edge cut. Expressed as a 2-variable generating function it is easily translatable into the corresponding partition function studied in statistical physics. In the current paper a comparatively efficient transfer matrix method is described for computing the generating function for the n×n grid with periodic boundary. We have applied the method to up to the 15×15 grid, in total 225 vertices. We examine the phase transition that takes place when the edge cut reaches a certain critical size. From the physical partition function we extract quantities such as magnetisation and susceptibility and study their asymptotic behaviour at the critical temperature.