Double Wall Research Articles

Understanding the Stability of Finite Double Walled Phenine and its Hybrid Structures using DFT Investigation

Abstract We have performed ab initio calculations based on density functional theory to investigate the structural and electronic properties
of finite double wall phenine nanotubes and their hybrid structures with armchair carbon nanotubes. The result shows that double wall
phenine nanotubes and the hybrid structures are quite stable. The stability of structure is strongly depends on inter-layer separation be-
tween the two tubes. The double walled phenine nanotubes are more stable than their corresponding pristine armchair tubes and exhibit
a semi-conducting nature with a HOMO-LUMO gap of 2.78eV and 2.80eV. The hybrid structures have a small electronic gap between
0.13eV-0.50eV similar to double wall armchair nanotubes. The results highlight the possibility of the synthesis of novel semi-conducting
double wall phenine structures.

New Spheromorphic Problematics Gaparella from the Lower Cambrian of Western Mongolia

From the lower part of the Tommotian Stage of the Lower Cambrian of Western Mongolia, ridge Hevte-Tsakhir-Nuruu described a new problematical sphaeromorhical microfossils Gaparella elenae sp. nov.; a new combination of generic and specific names Gaparella kuanchuanpuensis (Qian, 1977). has been proposed. Despite its very peculiar morphology, the genus Gaparella Missarzhevsky in Missarzhevsky et Mambetov, 1981 is more often mentioned in the list of synonyms of the genus Archaeooides Qian, 1977. The taphonomic variability of Mongolian Gaparella is shown and the morphology is reconstructed: these were hollow spheres, with a perforated double thin wall; between the holes, which were located chaotically on small elevations, a system of canals was developed; the wall may have been organic with an admixture of mineral components. Based on their lifestyle, these fossils were probably planktonic filter feeders. Their level of organization appears to have been consistent with Porifera; most likely these were juvenile forms.

Anatomical Structure and Bending Properties of Calamus zollingeri

The relationship between the structure and mechanical properties of materials has been a hot topic. However, there is a lack of research on the relationship between the structure of rattan and its mechanical properties. This study investigated the anatomical structure and bending properties of Calamus zollingeri, a commercially important rattan species. Samples were collected from different radial positions of the stem and analyzed for their microstructural features and mechanical properties. The distribution and morphology of vascular bundles (VBs), parenchyma cells (PCs), vessels, and fibers were examined using light microscopy. Bending tests were conducted to determine the modulus of rupture (MOR) and modulus of elasticity (MOE). Stepwise linear regression analysis was employed to explore the relationship between structural features and mechanical properties. The results showed that the diameters, lengths and distribution densities of the vessel elements were 280.32 μm, 2163.56 μm, and 3.68 pcs/mm2, respectively; the double wall thickness, lumen diameter, diameter, length, length–width ratio were 7.55 μm, 4.30 μm, 11.85 μm, 1569.39 μm, and 134.08, respectively; the tissue ratios of the vessel elements, fibers, sieve elements, and PCs were 22.76%, 20.5%, 4.83%, and 51.87%, respectively. The MOR of C. zollingeri was 55.77 MPa, while the MOE was 2669.11 MPa. The MOR of C. zollingeri was mainly affected by a double wall thickness of fiber and the tissue ratio of PCs, while the MOE was mainly affected by a double arm thickness of fiber and the tissue ratio of the vessel elements. This research provides valuable insights into the structure–property relationships of rattan, which can inform its optimal utilization in various applications.

Acoustic performance prediction by means of a statistical energy analysis of two adjacent workrooms used for conferences and educational proposes

AbstractThe current design of workspaces for companies is focused on minimalistic and modern styles prioritizing the aesthetic appearance with illuminated open spaces and the use of glass walls. If the acoustic performance is not considered, inappropriate Reverberation Times (RT) might lead to difficulties for hearing a speaker or teacher during courses and conferences, causing problems in the learning process. Additionally, there might be high sound transmission between adjacent work rooms. This paper presents the development and experimental validation of numerical models using Statistical Energy Analysis (SEA) to calculate the sound reduction index through a glass wall that separates two adjacent work rooms. These structures are dedicated to conferences and educational uses but cannot be properly used due to their high sound transmission and inappropriate reverberant time. The sound insulation prediction results are validated with experimental measurements carried out in the adjacent rooms under the standard ISO-140. Afterwards, a SEA model is used to provide some acoustic correction design guidelines for these types of constructions. To improve the acoustical performance in the rooms, the acoustic effects of different absorbent panels placed on the walls and ceiling were investigated, choosing a suitable material that complies with the recommended ranges of RT and with less amount of absorption area. The SEA model is then used to understand the effects of openings size between the panels that make up the glass wall on the sound insulation capacity between rooms. Finally, a SEA model is reformulated to quantify the effect of the application of double walls for sound insulation between rooms, which implies the increase of weighted sound reduction index in 9 dB with respect to measured data.

Design and Fabrication of a Novel Commercial Baking Oven

This study presents the design and fabrication of a novel wood-fired commercial oven for baking bread. The oven design features an external combustion chamber with heating elements which comprise stainless-steel pipes filled with magnesia starting from the combustion chamber to the 3 oven compartments. Each compartment has 12 heating elements laid under a mild steel sheet metal where the dough mould and its content is placed. Heat loss due to conduction, radiation and convection was prevented by the use of a double wall in both oven and combustion chamber compartments with silica brick and fibre glass respectively, and the oven was fired with wood to bake some dough. Findings showed that maximum temperature attainable by the oven was 700°C, however, the temperature required for baking bread is between 150°C and 180°C and the time was 25 minutes, the quantity of heat generated per time using 10 kg of wood was about 15,088 KJ. Furthermore, the physical appearance of the products was examined to meet consumers’ requirement and a total of 400 bread of 180 mm × 120 mm × 80 mm dimensions can be baked at a time. With slight modifications in the oven design, this number can be improved. The oven can be fired with other types of solid biofuels and can be used for metallurgical furnace applications like annealing, tempering and other heat treatments of metals.

The shear performance of DSCW-RC joints with lap-spliced steel bars

The double steel plate concrete composite shear wall (DSCW) structure combines the advantages of steel and concrete, offering high strength, stiffness, and durability. The joint formed by the DSCW and reinforced concrete foundation (RC foundation) was often unavoidable in engineering practice. Research related to the mechanical behavior of the DSCW-RC foundation is limited. This paper investigated the shear performance of DSCW-RC joints with lap-spliced steel bars. A total of seven specimens were designed and tested. The influences of steel plate thickness, steel bar arrangement, and stud spacing on the shear behavior of the joints are elucidated. The test results indicate that the predominant failure mode of the specimens occurred in the upper part of the local steel plate, with reinforcement yielding. While steel bar diameter and stud spacing minimally affected the shear strength, they significantly influenced the failure displacement at the joint interface. The failure deformation increased with increasing steel bar diameter and decreased with increasing stud spacing. Moreover, the thickness of the steel plate profoundly impacted structural shear strength and deformation, with both deformation and bearing capacity increasing with plate thickness. In addition, this study explores the force-transferring mechanism of such joints under shear load, offering a crucial reference for subsequent analyses of the composite force mechanism of DSCW - RC foundation joints.

Single-pot extractive double divided wall column for Acetonitrile, Ethanol, and water Separation: Design and control

An integrated single-pot double divided wall column (DDWC) process is designed for separating acetonitrile, ethanol and water into its constituent pure components using dimethyl sulfoxide (DMSO) as the homogenous extractive entrainer. Comparison with the recently reported side-stream extractive distillation (SSED) design with three columns shows the single-pot process to be more cost-effective and energy-efficient. The SSED process has a Total Annualized Cost (TAC) that is higher by 9.91% and an energy consumption that is higher by 7.27%. Also, a decentralized temperature inferential control system is shown to effectively reject large throughput and moderate feed composition changes to establish the controllability of the proposed design. The developed single-pot process is thus a promising alternative, particularly for space-constrained production facilities.

Enhancing cyclic performance of double steel plate shear walls with optimized stiffener configurations

Enhancing cyclic performance of double steel plate shear walls with optimized stiffener configurations

Identifying design criteria for implementing inherent safety in chemical process industries part 2: Design mechanism

AbstractInherent safety concepts are common knowledge today, but accidents with similar characteristics do recur. Research on accident causes found that design errors, especially equipment failure, contribute the highest percentage of accidents. The development of inherent safety tools has been increasing at a positive pace, but only a small number of these tools are applicable to equipment design. Ample amounts of inherent safety tools are only suitable to be used at the early design stage. This amplifies the fact that inherent safety tools are still conceptual (e.g., change process routes, change safer materials). This is in contrast to the circumstances, where tools are expected to reinforce the inherent safety of equipment. The objective of this research is to identify design mechanism that can help trigger design thinking for implementation of inherent safety in the chemical process industry. To identify such a design mechanism, 526 cases were collected, and knowledge of the mechanism was extracted from design changes and presented in this research paper. The mechanisms were classified according to equipment and inherent safety keywords. The significant design mechanisms from the overall summation were listed (turbulence, change heat transfer fluid, continuous removal, large surface area, corrosion resistance, seamless joint, thin film, dividing wall, on demand, and double wall).

Building Information Modeling and AI Algorithms for Optimizing Energy Performance in Hot Climates: A Comparative Study of Riyadh and Dubai

In response to increasing global temperatures and energy demands, optimizing buildings’ energy efficiency, particularly in hot climates, is an urgent challenge. While current research often relies on conventional energy estimation methods, there has been a decrease in the efforts dedicated to leveraging AI-based methodologies as technology advances. This implies a dearth of multiparameter examinations in AI-driven extreme case studies. For this reason, this study aimed to enhance the energy performance of residential buildings in the hot climates of Dubai and Riyadh by integrating Building Information Modeling (BIM) and Machine Learning (ML). Detailed BIM models of a typical residential villa in these regions were created using Revit, incorporating conventional, modern, and green building envelopes (BEs). These models served as the basis for energy simulations conducted with Green Building Studio (GBS) and Insight, focusing on crucial building features such as floor area, external and internal walls, windows, flooring, roofing, building orientation, infiltration, daylighting, and more. To predict Energy Use Intensity (EUI), four ML algorithms, namely, Gradient Boosting Machine (GBM), Random Forest (RF), Support Vector Machine (SVM), and Lasso Regression (LR), were employed. GBM consistently outperformed the others, demonstrating superior prediction accuracy with an R2 of 0.989. This indicates that the model explains 99% of the variance in EUI, highlighting its effectiveness in capturing the relationships between building features and energy consumption. Feature importance analysis (FIA) revealed that roofs (29% in Dubai scenarios (DS) and 40% in Riyadh scenarios (RS)), external walls (19% in DS and 29% in RS), and windows (15% in DS and 9% in RS) have the most impact on energy consumption. Additionally, the study explored the potential for energy optimization, such as cavity green walls and green roofs in RS and double brick walls with VIP insulation and green roofs in DS. The findings of the paper should be interpreted in light of certain limitations but they underscore the effectiveness of combining BIM and ML for sustainable building design, offering actionable insights for enhancing energy efficiency in hot climates.

Physicochemical properties of coconut inflorescence sap (neera) under double wall open heating system

Physicochemical properties of coconut inflorescence sap (neera) under double wall open heating system

A Review on Seismic Performance of Steel Plate Concrete Walls with Openings

Double steel plate concrete combination wall is a new structural form, with reinforced concrete structure does not have the advantages: both sides of the steel plate can be used as a template for concrete pouring, control the width of cracks in the concrete and extension of leakage, to avoid premature collapse, out of the working state, and at the same time can mitigate the hazards of the impact of the flying object to play a protective role; filled with concrete to enhance the stability of the steel plate to avoid the premature bulging of the steel plate. Drumming. Opening holes in the shear wall structure will not only reduce the integrity of the shear wall, but also affect its seismic performance. When faced with different functional requirements, the selected opening design program will also be different, but for the specific hole arrangement method there is no clear provisions given in the code. Therefore, a large number of scholars at home and abroad have carried out research on shear walls with different opening sizes, locations or shapes by means of experiments and simulations to analyze the influence of these factors on shear walls with openings first.

Compression behavior of truss-reinforced double steel plate-recycled aggregate concrete composite low wall: A numerical investigation

Truss-reinforced double steel plate-recycled aggregate concrete composite (TSRCC) walls are novel composite walls that provide an effective way to recycle waste concrete. Based on the results of relevant tests, the finite element (FE) software ABAQUS was adopted to simulate the axial compression performance of the TSRCC low wall. Influences of different parameters on the mechanical response of the TSRCC low wall were studied. Finally, the results of the parametric analysis were compared with those obtained by relevant calculation formulas. The comparison revealed that main factors affecting the bearing capacity include the replacement ratio of recycled coarse aggregate, the strength and thickness of the steel plate, the strength of recycled aggregate concrete (RAC), the truss horizontal spacing, the wall thickness and width. The bearing capacity calculated by the T/CECS 625–2019 method was the closest to the FE simulation result, while the AISC 360–16 method presented the most conservative estimate.

The investigation of double wall cooling configuration with spherical cavity

Double wall cooling is an efficient cooling method for turbine blade. Commonly used double wall cooling configurations contains a cubic cavity between two walls. Chaos flow flied in the cavity impedes heat transfer. In this research, a new spherical cavity was proposed, traditional cubic cavity was replaced by several spherical cavities, film hole located on the top of spherical cavity, and impact hole located at the button of spherical cavity. Adjacent spherical cavities were connected by channel. Different spherical cavities were established and numerical simulation was used to check their performance. The influence of blowing ratio, channel, film hole diameter, spherical cavity diameter was analyzed. The performance of cavities was also compared with common double wall cooling configurations. According to the result, when blowing ratio was 0.3, spherical cavity increased cooling effectiveness by 45.6% maximumly compared to common configurations. As for coolant consumption, spherical cavity needs less coolant than common configurations to achieve the same cooling effectiveness. What's more, film hole located at −45° position was benefit for cooling, and cooling effectiveness would increase further when spherical cavity diameter was enlarged.

Development of double-walled bellows for ITER VUV spectrometer systems

This study describes the design and development of double-walled bellows used in ITER's vacuum ultra-violet (VUV) spectrometer systems. These bellows were designed to accommodate port plug displacement resulting from the thermal expansion of the ITER vacuum vessel and other interface loads. The three VUV spectrometer systems under development—the VUV core survey spectrometer, divertor-VUV spectrometer, and VUV-edge spectrometer—are intended to measure the VUV spectrum to monitor impurity species in the plasma. While the ex-vessel components of ITER VUV spectrometers in the interspace and port cell areas, are fixed to the tokamak building, the closure plate of the port plugs, to which the sight pipes are attached, is expected to move by several centimeters both vertically and radially owing to the vacuum vessel's thermal expansion. As a result, the structural integrity of the system requires a flexible structure that can compensate for displacement caused by thermal expansion. To address this need, two types of double-walled bellows were developed, gimbal bellows for lateral displacement and axial bellows for axial displacement. These were developed in accordance with the ASME SEC.VIII code and EJMA standard to meet ITER's safety and vacuum requirements. A double wall is mandated for vacuum bellows due to their vulnerability in terms of vacuum safety. The structural integrity and functionality of the designed bellows were confirmed through functional tests on the manufactured prototype.

Anatomical Features and Morphometric Characteristics of the Sphenoidal Sinus in MRI Studies.

Differential access to pathological sellar processes and adjacent regions is determined by the anatomic structures identified through diagnostic imaging. Both direct endonasal access (microscopic or endoscopic) and sublabial access utilize the sphenoid sinus (SS) as the primary surgical pathway. Critical factors include the pneumatization of the sinus, its intermediate septa, and the presence of a double wall, consisting of a connective tissue membrane along the dorsal wall of the SS. The present study aims to demonstrate the significance of the size and type of the SS based on MRI measurements. The type of SS, its pneumatization, and the proximity of adjacent brain structures are crucial for different surgical approaches to the SS and pituitary fossa. In neurosurgical practice, six main types of sinuses are recognized: sphenoid body type, lateral type, clival type, lesser wing type, anterior type, and combined type. Failure to consider these variations can lead to damage to the cavernous sinus, Meckel's cave, nerve structures in the middle cranial fossa, planum sphenoidale, suprasellar region, and vital brainstem structures located on the clivus. Randomly included MRI measurements were conducted on 112 patients from Pulmed University Hospital, Plovdiv, Bulgaria, categorized into two cohorts based on gender, with mean ages of 51 years for men and 47.8 years for women. The measurements, recorded in centimeters, were obtained using two imaging software programs, RadiAnt DICOM Viewer (Medixant, Poznan, Poland) and Weasis DICOM Viewer (Nicolas Roduit, https://github.com/nroduit/Weasis). No statistically significant differences were observed between the measurements produced by the two programs. Measurements of the SS were taken in two equal groups, using three different projections: axial, sagittal, and coronal. The results for height, width, and depth showed average sizes of 2.73-3.04 cm in axial projections, 1.70-2.64 cm in sagittal projections, and 2.86-3.03 cm in coronal projections. The minor differences between axial and coronal measurements of the same parameters (height and width) are statistically acceptable and attributed to the varying angles of the MRI scans. These measurements are crucial for planning surgical access to the sellar and parasellar regions, determining the necessary bony resection of the posterior wall of the SS, and preventing complications from excessive bony trepanation.

Application of multi-stage ionic wind technology in glass curtain walls for enhanced thermal insulation performance

Glass curtain walls are widely used in architecture due to their aesthetic appeal and brightness. However, their thermal insulation performance is relatively poor, with natural convection within the cavity contributing significantly to overall heat transfer. To enhance the thermal insulation of double glazing curtain walls and reduce building energy consumption, we propose installing a multi-stage ionic wind generator on the curtain wall to weaken natural convection using ionic wind.In this paper, we introduce an ionic wind generator based on a wire-plate electrode configuration arranged in a plane, demonstrating that it follows the same discharge laws as electrodes arranged in space. An experimental platform was established to investigate the effect of multi-stage ionic wind on reducing natural convection within the cavity. The results indicate that ionic wind interference effectively weakens natural convection, thereby improving the thermal insulation of the glass curtain wall. Specifically, when voltages of 10 kV, 15 kV, and 20 kV are applied, the overall heat transfer coefficient of the double glazing cavity decreases by 5.56 %, 10.35 %, and 14.39 %, respectively. Numerical simulations visually record the process of weakening natural convection and provide electric field data for ionic wind. Additionally, we evaluated the Coefficient of Performance (COP) of the experimental cavity, which reached a maximum of 2.4 in our experiments. Future research can focus on optimizing energy efficiency. This study innovatively explores the feasibility of improving the thermal insulation of glass curtain walls using ionic wind, contributing to reducing building operational energy consumption and mitigating global warming.

Design and control of a novel multi-product extractive dividing wall column process for recycling organics from wastewater

The wastewater from a pharmaceutical plant consists of a tetrahydrofuran/isopropanol/water azeotrope. This investigation utilizes dimethyl sulfoxide as an extractant and employs an extractive dividing wall column to separate the aforementioned azeotrope. The extractive dividing wall columns are constructed with single, double, and triple partition walls, and a multi-objective genetic algorithm is used to optimize the operational parameters of the separation process. Of these columns, the extractive dividing wall columns with triple partition walls show the most favorable economic, environmental, and energy utilization performance, and it has a lower risk of combustion and explosion. Compared to the conventional design, the use of triple-partition extractive dividing wall columns results in a 22.13 % and 10.54 % reduction in total annual cost and CO2 emissions, respectively, and an increase in thermodynamic efficiency of 2.66 %. Studying the dynamic characteristics of this process reveals its excellent dynamic controllability.

Responses of Physiological Traits and Soil Properties in Pinus thunbergia and Euonymus japonicus Saplings under Drought and Cadmium (Cd) Stress

Pinus thunbergii and Euonymus japonicus are two species commonly found in arid and semi-arid areas; however, their responses in terms of physiological traits and soil properties under drought and cadmium (Cd) stress are not clear. In this study, we carried out single and combined stress treatments consisting of drought and Cd on saplings of P. thunbergii and E. japonicus and investigated the responses in terms of the physiological traits and soil properties of both species. For both species, under single Cd stress, Cd was observed in both the xylem and phloem, while the root Cd2+ flow rate fluctuated at different levels of Cd stress. Under both single and combined stress, as the stress level increased, the abscisic acid (ABA) content of the leaves and roots increased significantly, while the indole-3-acetic acid (IAA) content of the leaves and roots decreased significantly. Moreover, the non-structural carbohydrate (NSC) content of the leaves, stems, and roots, as well as the leaf chlorophyll content, decreased significantly. Under drought stress, the xylem water potential and hydraulic conductivity significantly decreased, which was exacerbated by Cd stress; this led to a more significant decrease in water potential and hydraulic conductivity under the combined stresses. Meanwhile, no significant changes in the conduit lumen diameter and double-wall thickness were observed, except for the double cell wall thickness of the P. thunbergii tracheid, which increased. In addition, both the single stresses and the combined stress of drought and Cd induced significant changes in the soil properties of the two species, i.e., the ammonium nitrogen, nitrate nitrogen, and effective phosphorus of the soil increased significantly, and the increase in content was more significant under combined stress. The diversity of the soil microbial community of P. thunbergii saplings significantly increased, while no change was found in its microbial community abundance under the single stresses and combined stress; however, the diversity and abundance of the soil microbial community in E. japonicus saplings showed the opposite pattern, which indicates that the effect of Cd on soil microorganisms is more significant than the effect of drought. The activity of sucrase and catalase in P. thunbergii soil fluctuated under the single stress and combined stress when compared, and the activity of sucrase in the soil of the E. japonicus species decreased. However, its catalase activity increased significantly under the single drought and Cd stress and combined stress when compared. We found that the combined stresses exacerbated the effects of the single stress in both species. Our study provides more detailed information on the responses in terms of the physiological traits and soil properties of the two species under single and combined stress consisting of drought and Cd.

Manipulation of Moiré Superlattice in Twisted Monolayer-multilayer Graphene by Moving Nanobubbles.

In the heterostructure of two-dimensional (2D) materials, many novel physics phenomena are strongly dependent on the Moiré superlattice. How to achieve the continuous manipulation of the Moiré superlattice in the same sample is very important to study the evolution of various physical properties. Here, in minimally twisted monolayer-multilayer graphene, we found that bubble-induced strain has a huge impact on the Moiré superlattice. By employing the AFM tip to dynamically and continuously move the nanobubble, we realized the modulation of the Moiré superlattice, like the evolution of regular triangular domains into long strip domain structures with single or double domain walls. We also achieved controllable modulation of the Moiré superlattice by moving multiple nanobubbles and establishing the coupling of nanobubbles. Our work presents a flexible method for continuous and controllable manipulation of Moiré superlattices, which will be widely used to study novel physical properties in 2D heterostructures.