Window Dimensions Research Articles

Adsorption and reaction of sulfachloropyridazine sulfonamide antibiotic on a high silica mordenite: A structural and spectroscopic combined study

Owing to their acidic nature, sulfonamide antibiotics concentrate in anionic form in water bodies where they can remain unchanged for long periods of time, accounting for great concern for antibiotic-resistance issues. In this study the removal of sulfachloropyridazine (4-amino-N-(6-Cl-3-pyridazinyl)benzene sulfonamide) antibiotic from water by adsorption on a high silica mordenite with channel window dimension comparable to that of the antibiotic, and with a significant concentration of internal silanol groups due to the dealumination process, was investigated. The adsorption of sulfachloropyridazine by mordenite at room temperature was completed within 4h with the maximal amount of adsorbed antibiotic of 15.1% zeolite dry weight. The desorption trials elucidated the irreversibility of the adsorption process. The embedding of sulfachloropyridazine into mordenite channels was confirmed by a combined XRPD and FTIR study. Rietveld structure refinement revealed that the incorporation of sulfachloropyridazine molecules caused changes in the dimension of the zeolite channel systems, when compared to the parent zeolite, and a close vicinity of the heterocycle ring nitrogen to the oxygens of mordenite side pocket. FTIR revealed a strong perturbation of the vibrational modes of both the pyridazinyl ring and mordenite silanol groups upon antibiotic adsorption. When the adsorption was conducted at 65°C, an unfavourable temperature effect was highlighted and, interestingly, sulfachloropyridazine transformed with 100% selectivity to 4-amino-N-(6-hydroxyl-3-pyridazinyl)benzene sulfonamide. A nucleophilic aromatic substitution (SNAr) mechanism was suggested for the formation of the reaction product. It is proposed that the H-bond between mordenite silanol groups and pyridazine nitrogen atom, clearly detected by FTIR, stabilize in the ring partial positive charges favouring the displacement of the chloride leaving group.

Global behaviors of enclosure fire and façade flame heights in normal and reduced atmospheric pressures at two altitudes

Enclosure fire safety design and regulations are commonly specified for normal pressure conditions at sea level. There is need however to extend the design requirements for conditions in reduced pressure atmosphere such as city at high altitude, in which the corresponding fundamental behaviors should be clarified first. Experiments are designed and carried out in this work at two different altitudes (Hefei city: 50m, 1atm; Lhasa city: 3650m, 0.64atm) in a 0.4m cubic fire enclosure with various window dimensions and an attached 1m (wide)×2.2m (high) façade with and without an opposite facing wall. Gas temperature profiles inside the enclosure and façade flame heights are measured to find out their behavioral changes for these two pressures and to develop global correlations. It is found that, for a given fuel supply rate the gas temperature inside the enclosure is lower while the outside flame is higher in the reduced pressure atmosphere, owing to the lower fuel consumption inside the enclosure and air entrainment into the flame. The flame height (without a facing wall) normalized by a characteristic window length scale ℓ1 can be well correlated with the dimensionless excess heat release rate, but being a bit higher due to lower entrainment or larger fluctuations at lower pressure, but can be accounted for globally by a correction factor of 0.8. In addition, the characteristic length scale ℓ3 representing the horizontal projection of the flame is higher, and thus, the critical distance of the facing wall from the enclosure, at which interaction of the façade flame and the opposite facing wall starts, is larger at lower pressure. The relative higher façade flame height and the larger critical façade-to-facing-wall distance suggest that hazards of enclosure facade fires at low pressure (high altitude) are higher and it need more conservative regulations than those at standard pressure. By accounting for their behavioral changes, global models have been correlated for gas temperature inside the enclosure as well as façade flame height without and with an opposite facing wall applicable for these two atmospheric pressures. The present results and global correlations in both normal–and reduced pressure atmosphere provide fundaments of guideline for regulations extension to high altitude and are a significant supplement and improvement over previous results in literatures.

SU-D-213AB-03: Design Optimization of a HDR Ir-192 Brachytherapy Skin Applicator Using Monte Carlo-Based Dosimetry.

AccuBoost® applicators are designed to deliver boost dose after whole breast irradiation in substitution for electron boost. By augmenting the current design through adding a wedge inside the applicator and atungsten window above the skin surface, the AccuBoost applicators can be used to treat skin cancer. This study aimed to design a skin applicator that could deliver brachytherapy in a conformai and homogeneous manner to the skin while minimizing OAR dose. The 6 cm round AccuBoost applicator served as the foundation for variations of an internal cone, internal wedge, and external window. Monte Carlo (MC) methods (MCNP5)were used for dose characterization and design optimization of these tungsten-alloy components. Specifically, the cone, wedge, and window dimensions were iteratively varied in MC simulations based on HDR Ir-192 dose distributions having (0.5 mm)̂2 voxels in a soft tissue phantom. The design goal was an applicator that can protect tissue > 5 mm while providing lateral dose conformity and a homogeneous dose distribution for tissue < 3 mm. The internal wedge angle governed field size to be irradiated, limiting depth-dose spread into the phantom. Dose conformity was enhanced by the internal cone and collimating window. Window thickness increased required treatment time, where 3 mm was determined to be optimal when considering tradeoff between depth dose and dose rate. With a lesion thickness of 3 mm and setup uncertainty of 1 mm, the optimal design provided better lateral coverage at d = 5mm. Here, the dose was less than 30% of that within the treatment aperture. Standardized criteria were established for dose optimization of a skin applicator. Using these criteria and MC methods, an optimized design was obtained. Optimization is underway for other applicator diameters. Clinical evaluation within a 3D treatment planning system and comparison with other brachytherapy skin applicators is ongoing. Prof. Rivard is a stakeholder of Advanced Radiation Therapy, LLC.

OFDM channel estimation with dispersive fading channels

In this paper, we studied the channel estimation problem for the orthogonal frequency division multiplexing (OFDM) system when the statistics of the multi-path fading channel is not known or partial known. A channel estimation approach based on polynomial approximation of the channel response is proposed. The pilot symbols are periodically inserted the channel responses for entire OFDM data sequence for exploiting channel correlation in both time and frequency domain, which is obtained from a time-variant frequency-selective Rayleigh fading channel model. Simulation shows that the method is robust to different channel statistics. Moreover, a window dimension adaptation algorithm is proposed to adapt the channel estimator to the channel statistics which further improves the robustness of the system.

Prediction of the spread of smoke in a huge transit terminal subway station under six different fire scenarios

A fire at a subway station can cause tremendous loss of property and heavy casualties, and smoke has been reported to be the main cause of these casualties. This article reports the use of Large Eddy Simulation (LES) simulation to study the dispersion of fire-induced smoke that is buoyancy driven in a subway station. This station was located within a huge transit terminal at Xi’an, China. The influence of natural and mechanical ventilation was studied in this station, which has atrium height ranging from 0 to 15m, roof window dimensions of 1×1m2 and 5×1m2, and rates of air change ranging between 5 and 11h−1. In addition, six different fire-source locations with heat-release rates (HRRs) of 4 and 7.5MW are discussed. Four grid systems were compared, and the sensitivity of these grid systems was checked to ensure grid independence. Preliminary analysis of results indicates that the atrium of a subway station poses significant limitations on the horizontal dispersion of smoke. A large soot-density gradient has also been observed in stations with a high atrium. An exponential relationship has been proposed to define the correlation between atrium height and duration of smoke filling, with a relative coefficient (R) of 0.9995. The results indicate that mechanical ventilation can markedly control the spread of smoke in the horizontal direction but it has little effect on the dispersion of smoke in the vertical direction. If a fire starts directly below the atrium, most of the smoke generated will converge toward the upper regions of the atrium. In addition, the simulation helps predict the maximum soot density of smoke generated by different heat releases (4 and 7.5MW).

On the uncertainty of digital PIV and PTV near walls

The reliable measurement of mean flow properties near walls and interfaces between different fluids or fluid and gas phases is a very important task, as well as a challenging problem, in many fields of science and technology. Due to the decreasing concentration of tracer particles and the strong flow gradients, these velocity measurements are usually biased. To investigate the reason and the effect of the bias errors systematically, a detailed theoretical analysis was performed using window-correlation, singe-pixel ensemble-correlation and particle tracking evaluation methods. The different findings were validated experimentally for microscopic, long-range microscopic and large field imaging conditions. It is shown that for constant flow gradients and homogeneous particle image density, the bias errors are usually averaged out. This legitimates the use of these techniques far away from walls or interfaces. However, for inhomogeneous seeding and/or nonconstant flow gradients, only PTV image analysis techniques give reliable results. This implies that for wall distances below half an interrogation window dimension, the singe-pixel ensemble-correlation or PTV evaluation should always be applied. For distances smaller than the particle image diameter, only PTV yields reliable results.

Developing a Simple Damage Model for the Long-Term Durability of Acrylic Foam Structural Glazing Tape Subject to Sustained Wind Loading

AbstractThis article presents a simple linear damage accumulation model that may have applicability for predicting damage from sustained winds in double-sided acrylic foam tape used to attach curtain wall glazing panels to buildings. The purpose of this model is to investigate the possible cumulative effects of years of wind-induced stresses that are less than the peak stress expected during a 3-s gust, as specified in current design guidelines established by the structural glazing industry and adopted by the manufacturer of these structural glazing tapes. Several representative wind histories are selected to provide input data for the model. These wind histories provide multiple years of average wind speeds over either 10-min or 1-h recording intervals, depending on the source. Each entry in a wind speed history is converted to stress on the glazing adhesive tape on assumed window dimensions using the standard wind loading design equations of ASCE 7-05. A creep rupture prediction equation, developed from...

How to reduce short column effects in buildings with reinforced concrete infill walls on basement floors

Band windows are commonly used in reinforced concrete structures for the purpose of ventilation and lighting. These applications shorten the lengths of the columns and, consequently, they are subject to higher shear forces as compared with those of hollow frames. Such short columns may cause some damages during earthquakes. Hence, these effects of short columns should be minimized by choosing the dimensions of the band windows properly in order to prevent serious damages in the structure. This can be achieved by taking into account the parameters that are crucial in causing short column effect. Hence, in this study, the effects of those parameters such as the widths and heights of the band windows, the number of bays and storeys within the frame, and the heights of storeys are examined. The effects of the parameters are analyzed using time history analysis. One of the important results of these analyses, is that, the widths of the band windows should be less than 60% of the clear span between the columns, whereas, their heights should be greater than 35% of the clear storey height in order to decrease the short column effects substantially during the design of the reinforced concrete structures.

The Natural Primary Type of Energy-Saving in Changangtang Ancient Village in Huadu District, Guangzhou

Taking Changangtang ancient village in Guangzhou as a case, this paper investigated the village location, the village layout, as well as building structures and building materials regarding their contributions to energy saving. It is found that the location and the surrounding of artificial river system form natural energy-saving environment, the overall layout of “comb pattern” complies to the local predominant wind direction in summer which go further in reducing the energy consumption in building, the courtyard enhances the ventilation and lighting, and the "Black brick with loam brick inside " form of material for wall, materials used for roofs, and dimensions of doors and windows all contribute to energy-saving.

Richard Vollenweider: an original thinker and one of his last ideas, moving correlations

Richard Vollenweider: an original thinker and one of his last ideas, moving correlations

Guest-Specific Double- or Single-Step Adsorption in a Flexible Porous Framework Based on a Mixed-Ligand System

A 2D flexible metal-organic porous solid, {[Ni(1,3-adc)(bpp)(H2O)2](H2O)(EtOH)}n (1), has been synthesized using flexible organic linkers. The desolvated framework, {[Ni(1,3-adc)(bpp)]}n (1'), undergoes structural contraction and exhibits double-step hysteretic adsorption for CO2, H2O, and MeOH and single-step gate-opening behavior with EtOH. These observations are correlated with the effect of the polarity and window dimension of the pore to the corresponding adsorbate molecules.

Construction of a 2D Rectangular Grid and 3D Diamondoid Interpenetrated Frameworks and Their Functionalities by Changing the Second Spacers

AbstractThree new metal–organic ZnII frameworks, {[Zn(bipy)(1,4‐ndc)(H2O)2]·2H2O} (1), {[Zn(bpe)(1,4‐ndc)]2·2DMF} (2), {[Zn(bpee)(1,4‐ndc)]2·2DMF} (3) [bipy = 4,4′‐bipyridyl, 1,4‐ndc = 1,4‐naphthalenedicarboxylate, bpe = 1,2‐bis(4‐pyridyl)ethane, bpee = 1,2‐bis(4‐pyridyl)ethylene], have been synthesized by using mixed‐ligand systems under solvothermal conditions and characterized structurally by single‐crystal X‐ray diffraction. Compound 1 has a 2D structure with 44‐sql net topology, whereas 2 and 3 have a 3D diamondoid structure with interesting fourfold interpenetrated topology. Topological analyses of the diamondoid nets in compounds 2 and 3 reveal a 4‐connected net with 66 topology. Thermogravimetric experiments suggest that the solvent‐free compounds 1–3 are stable up to 370, 330, and 280 °C, respectively. The grids of 1 stack in –ABCD– fashion without any regular channel structure. Desolvated compound 2 (2′) selectively adsorbs CO2 over N2, and such discrimination is regulated by the restricted window dimension of the channels. Solvent vapor (H2O, MeOH, and EtOH) adsorption studies with 2′ suggest a hydrophobic nature of the pore surface. Gas and vapor adsorption studies with 3′ reveal no uptake, which can be correlated to a smaller pore size relative to the kinetic diameter of the respective adsorbates.

Technical parameters of drawing and coal-gangue field movements of a fully mechanized large mining height top coal caving working face

Under fully mechanized, large mining height top coal caving conditions, the shield beam slope angle of the support increases due to the enlargement of the top coal breaking and caving space. This results in a change of the caving window location and dimensions and, therefore, the granular coal-gangue movement and flows provide new characteristics during top coal caving. The main inferences we draw are as follows. Firstly, after shifting the supports, the caved top coal layer line and the coal gangue boundary line become steeper and are clearly larger than those under common mining heights. Secondly, during the top coal caving procedure, the speed of the coal-gangue flow increases and at the same drawing interval, the distance between the coal-gangue boundary line and the top beam end is reduced. Thirdly, affected by the drawing ratio, the slope angle of the shield beam and the dimensions of the caving window, it is easy to mix the gangue. A rational drawing interval will cause the coal-gangue boundary line to be slightly behind the down tail boom lower boundary. This rational drawing interval under conditions of large mining heights has been analyzed and determined.

Isomorphous framework cation substitution in the alumosilicatesodalites: synthesis, structural and spectroscopic studies of nitritecontaining phases

AbstractPartial substitution of aluminium with gallium in the Na8[Al1–yGaySiO4]6(NO2)2sodalite system (y= 0–1) revealed an extensive isomorphous miscibility. Each composition (y= 0–1) is isotypic to either the alumosilicate or gallosilicate end members (y= 0 or 1, respectively). The Al/Ga ratio was controlled by selective initial stoichiometries in the direct hydrothermal syntheses. The samples were investigated by X-ray powder diffraction, SEM, FTIR and29Si MAS NMR spectroscopies. The gallium concentration in the framework was calculated using the X-ray data Rietveld refinement, which was always lower than the feed concentration in each composition. The cell parameter and tilt angle increased, while the T—O—T angle and six-ring window dimension decreased with increasing gallium content in the framework. The Al/Ga—O distance is the mean of Al—O and Ga—O distances and increases with increasing gallium content. In contrast, the Si—O distance fluctuates close to 163 pm with increasing gallium insertion. The broadening of the XRD peaks in the patterns with mid-range gallium concentrations (y= 0.35–0.70) is associated with the formation of Al-rich and Ga-rich domains, which is explained in terms of Al/Ga—O distances and average crystal size with respect to Al/Ga ratio in the framework. The domains are assumed to be smaller than the coherence length of the X-ray radiation but large enough to detect by MAS NMR techniques.

Window Sizing Procedures based on Vertical Illuminance and Degree of Discomfort Glare in Buildings Interiors

This study outlines a simplified mathematical approach to determine window dimensions for a given room based on two lighting quality indicators, namely, discomfort glare and vertical illuminance. The former represents visual comfort and is expressed in terms of daylight glare index (DGI). The latter reflects on the aspect of receiving sufficient light exposure to maintain optimal health and psychological wellbeing. It is represented by vertical illuminance at the eye level. The result offers a formula that puts forward a simple relationship between the window width, the window height and a specific (desired) depth of a given point in the space. A generic design scenario is used to illustrate the current method. The examined daylighting design criteria are of DGI=20 and Ev= 2500 lux. In conclusion, this paper proposes the glare criterion as additional to existing national window sizing procedures based on critical illuminance levels (or minimum daylight factor on the working plane corresponding to the critical visual tasks) and critical exterior conditions (that occur with absence of sunlight and a CIE Overcast Sky standard).

Cure width potential for MOD resin composite molar restorations

Objectives To investigate the capability of modern light-curing units exhibiting differences in emission spectra and light source exit window dimensions, for “one-shot” full-width curing of extensive (molar MOD) resin composite restorations. Method Specimens of Tetric (TT), Tetric Ceram HB (TC), Tetric Evoceram (TE) and Tetric Ceram Bleach (TB) resin composites containing varying ratios of Lucirin (TPO) and/or camphorquinone (CQ) photoinitiators were packed into a bar-shaped mould (12 mm length × 2 mm width × 2 mm thickness). Each product was irradiated using a halogen (Optilux 401; QTH), a conventional LED (LEDemetron; LED) and two so-called “third generation” oval-footprint LED light-curing units (LCUs) of the same model. The latter featured bimodal emission spectra (blue and ultraviolet diodes) with either high (unmodified output) and approximately 50% (modified output) blue light intensity (UltraLume-5; ULs, ULm, respectively). Vickers hardness number was obtained across the lateral extent of the bar at 1 mm increments from the centre point on both upper and lower surfaces of the specimens. Results Significant linear relationships ( R 2 = 0.71–0.98) for each distance from the central position of all LCUs were identified between measured light intensity and corresponding upper and lower surface hardness values for each product ( P < 0.05). No significant differences ( P > 0.05) were recorded in total upper surface hardness of TC or TE cured with LED (68.7 ± 3.2 and 70.5 ± 2.5) or ULm (56.8 ± 2.0 and 57.7 ± 2.0). However, upper surface hardness of TT (CQ only) cured with ULm was significantly decreased ( P < 0.05) compared with other LCUs. When the ratio of hardness at the edge to central positions of the bar-shaped specimens for either surface was calculated, no significant difference ( P > 0.05) was identified for TB (containing TPO and decreased CQ) cured with either ULs or ULm ( P > 0.05) and was significantly increased (P < 0.05) when cured with ULs compared with LED and QTH. Significance Variability in light intensity across the curing-tip face, spectral output of dental light-curing units and differences in product photoinitiator chemistry all influence curing efficiency significantly across the width of extensive resin composite geometries.

Isomorphous gallium substitution in the alumosilicate sodalite framework: synthesis and structural studies of chloride and bromide containing phases

In the Na8[T1T2O4]6Y2sodalite system (Y= Cl, Br,T2= Si) the aluminium bearingT1position was successively substituted with gallium. The synthesized products represent the new composition Na8[Al1–yGay-SiO4]6Y2(0 ≤y≤ 1), where the Al/Ga ratio is calculated from the X-ray powder data Rietveld refinements. In each composition, the gallium concentration in the framework is observed lower than that in the initial feed. The linear expansion of the lattice parameters has been observed from [AlSiO4]6to [GaSiO4]6in increasing gallium concentration in the framework. The position of gallium and aluminium has been refined on a single crystallographic site. This result also indicates that both aluminium and gallium are indistinguishable and statistically distributed in theT1-sites. TheT1-O distance, therefore, offers an averaged magnitude of Al/Ga—O distance which increases with increasing gallium concentration. In contrast, the Si—O distance remains almost constant at 162.8 pm (2σ) and 163.4 pm (3σ) for chloride and bromide sodalites, respectively. The increasing average tilt of the (Al,Ga)O4and SiO4tetrahedra leads to a decrease of the six-ring window dimension as a consequence of increasing gallium incorporation in the framework. The simultaneous shortening of Na—O and Na—Cl/Br distances, with increasing gallium content, shows a direct interaction between the framework host and the enclathrated guest. Additionally, the tetragonal tetrahedron distortion and the framework oxygens-hybridization are discussed as a function of gallium concentration in the two new sodalite series.

VENTILATION OF SMALL MULTISPAN GREENHOUSE IN RELATION TO THE WINDOW OPENINGS CALCULATED WITH CFD

Ventilation is the most important aspect for the climatization of greenhouses. Heat, moisture, and CO2 are removed through ventilation. The effect of the dimensions of the ventilation windows and the orientation to the wind are investigated for a summer condition for a greenhouse design with a crop. Calculations are done using computational fluid dynamics (CFD). The ventilation rate and the temperature distribution in the greenhouse are compared for the different ventilation openings. The influence of wind direction is determined at 5 m s-1 windspeed together with the situation when no wind is present. The results show a large temperature gradient in the greenhouse. This gradient can be explained from the fact that the heat input is high causing a substantial temperature difference between the greenhouse air and the ambient. Ventilation increased as the window opening increased as expected. Opening only the window on the windward side resulted in almost double the ventilation than opening both the leeward and windward orientated windows. Side ventilation increases the ventilation especially when no wind is present

A large format membrane-based x-ray mask for microfluidic chip fabrication

X-ray lithography is a very good option for the fabrication of micro-devices especially when high aspect ratio patterns are required. Membrane-based x-ray masks are commonly used for high-resolution x-ray lithography. A thin layer of silicon nitride (Si3N4) or silicon carbide (SiC) film (1–2 µm) is normally used as the membrane material for x-ray mask fabrication (Wells G M, Reilly M, Nachman R, Cerrina F, El-Khakani M A and Chaker M 1993 Mater. Res. Soc. Conf. Proc. 306 81–9; Shoki T, Nagasawa H, Kosuga H, Yamaguchi Y, Annaka N, Amemiya I and Nagarekawa O 1993 SPIE Proc. 1924 450–6). The freestanding membrane window of an x-ray mask, which defines the exposing area of the x-ray mask, can be obtained by etching a pre-defined area on a silicon wafer from the backside (Wang L, Desta Y, Fettig R K, Goettert J, Hein H, Jakobs P and Chulz J 2004 J. Micromech. Microeng. 14 722–6). Usually, the window size of an x-ray mask is around 20 × 20 mm because of the low tensile stress of the membrane (10–100 MPa), and the larger window dimension of an x-ray mask may cause the deformation of membranes and lower the mask quality. However, x-ray masks with larger windows are preferred for micro-device fabrication in order to increase the productivity. We analyzed the factors which influence the flatness of large format x-ray masks and fabricated x-ray masks with a window size of 55 × 55 mm and 46 × 65 mm on 1 µm thick membranes by increasing the tensile stress of the membranes (>300 MPa) and optimizing the stress of the absorber layer. The large format x-ray mask was successfully applied for the fabrication of microfluidic chips.

The Contribution of Roller Shutters to Noise Insulation of Façades

This paper describes an experimental study of the influence of roller shutters on noise insulation of façades. The study is based on the results of a set of tests carried out in laboratory and in a new residential building, which is typical of Portuguese cooperative construction. The window system (glazing and frame, plus the roller shutter) was first tested in a laboratory. In situ, the tests were performed in two rooms having different window dimensions. The measurements were in accordance with international standards, using a loudspeaker as noise source. The considered shutters positions were: totally opened, half closed, partially closed and completely closed. Additionally, in situ measurements with the window open were also done. The results show that the façade transmission loss curve is affected by shutter position. The investigation highlighted the importance of shutter position when the window is open and the discrepancy between laboratory and in situ measured values.