Walls Of Box Research Articles

Assessment of Urban Farming Production, and Contribution to the Households’ Livelihood: A Case of Kigali City and Musanze District

Agriculture plays an important role in the economic growth and food security control in developing countries including Rwanda. This research study was carried out in Kigali and Musanze. Urban farming is one way to best use useless places closed inside household fences, resulting in high yields. Due to their short production cycle, Horticultural crops provide a quick response to emergency food needs, particularly in cities. These species have considerable yields that generate more income for farmers when used appropriately. The main objective of this study was to analyze the factors influencing urban farming production, profitability, and contribution to the households’ livelihoods in Rwanda. The population of interest for this research study constituted smallholder farmers of vegetables and fruits in Kigali and Musanze cities. The sampling unit was the garden household. A multistage sampling technique was employed involving purposive sampling of four districts Gasabo, Kicukiro, Nyarugenge, and Musanze. The study used a sample frame of 1085 population and a sample size of 112 respondents. The results from the study indicated that ten factors over fourteen have a positive influence on urban farming production while four have a negative influence in the study area. The results also showed that the productive fruits grown are classified into five classes indicated in Figure 1. The results of the study revealed different places/methods used to grow vegetables/species and fruits such as bags, baskets and basins, hanging baskets, old wheels, pallet gardens, open ground, trellises, arches, shelves, fences window box walls. The results displayed that the crops do well in small areas/places closed inside the household’s fences. The results proved that urban farming contributed to the social economy through different parts example malnutrition control, money saving, and food security. The results pointed out that urban farming production is constrained by some challenges such as small owned parcels, lack of urban farming knowledge, lack of technologies, period of crop maturity, lack of capital, lack of awareness, habitation system, and infrastructures. However, urban farming development should be enhanced to maintain national food security and improve income for farmers.

An innovative deformation coordination method for analyzing distortion effects on box girders

A deformation coordination method is proposed in this study to account for the distortion effects on a box girder. The differential equation for distortion in vertical web box girders is derived based on the deformation coordination condition of the distortion angle, considering both external loads and internal forces. Subsequently, a comparative analysis is conducted to explore the similarities and differences between the differential equations derived from the proposed deformation coordination method, the plate element analysis method and the total potential energy variation method. The accuracy of the proposed approach is verified through bench-scale tests and numerical simulations. The findings indicate that the derived governing distortion differential equation and distortion attenuation coefficients in the proposed method align with those obtained from the plate element analysis method and the total potential energy variational method, which enhances the applicability to allow for the distortion equations to be obtained simply by calculating the distortion displacements. The analytical findings regarding the distortion warping normal stresses on the cross-sections of the box girders demonstrate favorable correspondence with the experimental results, displaying an acceptable error ranging from − 0.3% to 5.4%. Moreover, the peak of distortion warping normal stresses on the mid-span cross-section increases with higher span-to-depth ratios and height-to-thickness ratios of the web. Consequently, augmenting the thickness of the box wall proves to be an effective means of reducing the distortion effect in box girders.

Molecular dynamics simulation of the effect of temperature on the conformation of ubiquitin protein.

Ubiquitin, a ubiquitous small protein found in all living organisms, is crucial for tagging proteins earmarked for degradation and holds pivotal importance in biomedicine. Protein functionality is intricately linked to its structure. To comprehend the impact of diverse temperatures on ubiquitin protein structure, our study delved into the energy landscape, hydrogen bonding, and overall structural stability of ubiquitin protein at varying temperatures. Through meticulous analysis of root mean square deviation and root mean square fluctuation, we validated the robustness of the simulation conditions employed. Within our simulated system, the bonding energy and electrostatic potential energy exhibited linear augmentation, while the van der Waals energy demonstrated a linear decline. Additionally, our findings highlighted that the α-Helix secondary structure of the ubiquitin protein gradually transitions toward helix destabilization under high-temperature conditions. The secondary structure of ubiquitin protein experiences distinct changes under varying temperatures. The outcomes of our molecular simulations offer a theoretical framework that enhances our comprehension of how temperature impacts the structural stability of ubiquitin protein. These insights contribute not only to a deeper understanding of iniquity's behavior but also hold broader implications in the realm of biomedicine and beyond. All the MD simulations were performed using the GROMACS software with GROMOS96 force field and SPC for water. The ubiquitin protein was put in the center of a cubic box with a length of 8nm, a setting that allowed > 0.8nm in the minimal distance between the protein surface and the box wall. To remove the possible coordinate collision of the configurations, in the beginning, the steepest descent method was used until the maximum force between atoms was under 100kJ/mol·nm with a 0.01nm step size. Minimization was followed by 30ps of position-restrained MD simulation. The protein was restrained to its initial position, and the solvent was freely equilibrated. The product phase was obtained with the whole system simulated for 10ns without any restraint using an integral time step of 1fs with different temperatures. The cutoff for short-range electronic interaction was set to 1.5nm. The long-range interactions were treated with a particle-mesh Ewald (PME) method with a grid width of 1.2nm.

Structural design and dynamic characteristics analysis of braided composite two-stage gear transmission system

In order to realize the lightweight design of the transmission system, the braided composite material is applied to the two-stage gear transmission system. According to the structural characteristics of the two-stage gear reducer box, the whole box is designed to be assembled with the braided base and the box wall. Woven composite materials are applied to the web parts of mixed metal composite gears to realize the design goal of lightweight gears. Then, under the assumption of ignoring the influence of friction, bearings and other factors on the system, the dynamic model of the two-stage gear transmission system considering the box is established. By normalizing and dimensionless processing of the equations, the dimensionless differential equations of motion are obtained. The fourth-order Runge–Kutta method is used to analyze the relationship between the connection parameters and the dynamic characteristics of the system under the two working conditions of rigid and flexible connection between the composite base and the box wall.Through the analytical analysis of vibration displacement of two-stage gear reducer and box, the theoretical basis is found for the numerical analysis results. Finally, the dynamic characteristics of the transmission system are studied by vibration resonance analysis through high and low frequency interference. It is found that in a certain frequency range, with the decrease of the mass and moment of inertia of the transmission parts corresponding to the mixed metal composite gear, the amplitude-frequency characteristic Q of the lightweight gear and gearbox transmission system is slightly lower than that of the common gear and gearbox system, and the stability of the system is increased, and the dynamic characteristics of the system are improved.

Optimization Design of Insulation Materials and Thickness Based on Box Insulation Performance

To ensure that the air inside the box does not fall below -20 °C after cooling for four hours, With the help of CFD numerical simulation technology, the composition materials and thickness have been optimized and designed in this paper. In this paper, there are two kinds of materials for box wall panel, one is insulation material 1 with smaller specific heat capacity and steel, the other is insulation material 2 with larger specific heat capacity. The simulation analysis results of two types of box wall panels show that the air temperature at edges and corners is difficult to meet the requirements. By using local thickening, this situation can be greatly improved.

An added aroma changes the behaviour of domestic pigs in a novel situation aimed for stunning

The currently most widespread stunning method for pigs is high concentration of carbon dioxide (CO2), but this method is under scrutiny due to animal welfare deficits. One alternative method currently under development with potential to replace CO2 is nitrogen (N2) filled high expansion foam. While N2 does not elicit the same aversive behaviour as CO2, it is currently not known if the high expansion foam itself may be frightening to the pigs. Means to alleviate fear reactions to foam could consist of diverting pigs’ attention using aromas (an odour in combination with taste) of interest to them. The current study aimed to investigate if an added aroma (vanilla aroma) affected pigs’ avoidance and exploratory behaviour when exposed to air-filled high expansion foam in a foam box. The study included 50 pigs (30 females, 20 males) of 14–16 weeks of age, of different crosses between Yorkshire, Hampshire and Duroc. The pigs were randomly assigned to either the treatment with air-filled foam with added aroma or the control treatment with no added aroma, which they were exposed to in a foam box. The results showed that pigs with the aromatised foam expressed significantly more exploration behaviour directed towards the foam and box walls, but not towards the floor or the lid. The aromatised foam also resulted in a higher activity level of the pigs. In contrast to the hypotheses, pigs with aromatised foam expressed more avoidance behaviour, and escape attempts were exclusively observed when pigs were exposed to aromatised foam. Slipping events and frequency of vocalisations did not differ between pigs with and without aroma added to the foam. This study shows that an added aroma (taste and odour in combination) increased pigs’ exploration behaviour towards the foam, and thus could serve as a distraction for the pigs when inside a confined foam box. The results emphasise the importance of taking foam aroma into consideration in the further development of the N2-filled high expansion as a stunning method. The potential anxiety- or stress-reducing effect of any added aroma needs further investigation, and future studies should focus on assessing various types of aromas, and/or odours, as well as different concentrations of the compounds to determine which solution is most efficient in alleviating pig stress and anxiety.

Auto-agglomeration of dry ibuprofen powder under mechanical vibration: Effect of particle morphology and surface properties

This study investigates the effect of ibuprofen particle morphology and surface properties on its tendency to auto-agglomerate. Four diverse particle morphologies were produced by recrystallisation of ibuprofen from solvents with different polarities. The aspect ratio and the polar component of the recrystallised particles decreased as follows: methanol > ethanol > acetonitrile > hexane. The auto-agglomeration process was induced by mechanical vibration and the agglomerate strength was assessed by the Dispersion and Agglomerate Strength indices. Relatively strong agglomerates were detected only in the case of ibuprofen recrystallised from ethanol and acetonitrile, whereas weaker and no agglomerates were formed during mechanical vibration of ibuprofen recrystallised from methanol and hexane, respectively. It was found that tendency of ibuprofen powder to auto-agglomerate was associated with lower tribo-electric charges during mechanical vibration, hypothetically linked to the competitive advantage of electrostatic attraction of high surface polarity particles to the walls of the vibration box which can hinder particle-particle interactions. Crystal surface polarity could be altered by the crystallisation protocol and/or by particle breakage (exposing more crystal facets of high polarity) during mechanical vibration.

Study on damage effect of caisson wharves subjected to underwater explosion

This study aimed at investigating the destructive effect of explosion shock waves on caisson wharves in shallow water. First, underwater explosion tests were conducted on caisson wharves, full-size finite-element models of caisson wharf-water-explosive were established, and the accuracy of the models was verified by comparison. The destruction pattern and damage characteristics of the caisson wharf structure were then studied, and the effects of different explosion depths and different explosive quantities on the dynamic response of caisson wharves were analyzed. The results show that the destruction pattern of shock waves on the caisson wharf is manifested as plastic damage at the joint of the reinforced concrete (RC) box wall, shear destruction at the lower edge of the explosion loading wall, and integral displacement of the superstructure. When the scaled distance remains unchanged and the explosion depth and explosive quantity increase, the bottom reflection effect strengthens, turning the bending damage on the explosion loading wall into shear damage. By strengthening the performance of the RC box wall joints, explosion loading wall, and superstructure joints, and taking measures to reduce the reflection effect, the anti-explosion capacity of caisson wharves can be effectively improved.

Experimental investigation of airflow and heat transfer by natural convection in an insulated box with a Phase Change Material using a Particle Image Velocimetry technique

Airflow and heat transfer via natural convection in an insulated box with Phase Change Material (PCM) were experimentally investigated using Particle Image Velocimetry (PIV) and temperature measurements. The effects of PCM positions (side wall and lid) on flow pattern and temperature distribution were studied under empty and loaded conditions. Two loads were considered to study the obstacle effect and the influence of heat exchange with air. When PCM was either at the side wall or at the lid of the box, laminar flow was observed and the corresponding Rayleigh number was about 10 7 . Upward flow was always observed near the side walls of the box. When PCM was on the side, downward flow occurred along the PCM; in the empty case, flow was almost 2D but became 3D when the load was added. When PCM was on the lid, the air cooled in contact with PCM, detached from it and flowed downwards. In the empty case, downward flow was unstable, and with the load, it followed preferential pathways. The type of load exerted little effect on flow patterns at thermal steady state. Thus, a simpler load (extruded polystyrene) can be used in the first approach. The maximum velocity was about 0.1 m s −1 , so free convection cannot be neglected compared with conduction. Regarding temperature performance, PCM on the side and on the lid showed no substantial difference if gaps were left between the load and the walls or PCM. • Airflow and heat transfer due to natural convection in an insulated box with PCM were studied. • Effect of PCM positions on flow and temperature fields was investigated. • The highest observed air velocities in the box were around 0.1 m s −1 . • PCM position exerted no significant effect on maximum product temperature. • Gaps should be left between the product and the box walls or PCM.

Study of inverse natural convection-conduction heat transfer for in-line tube heat exchanger in a hot box with experimental data

BackgroundThe accuracy of the chosen flow model and near-wall treatment requires detailed experimental verification. It can affect the accuracy of the numerical results obtained. Thus, the selection of an appropriate flow model is important. However, a review of the literature found that few researchers have engaged in the inverse convection-conduction conjugate heat transfer problem. MethodsThis study uses an inverse computational fluid dynamics (CFD) method combined with the least squares method and overdetermined experimental data to predict the unknown heat transfer rate Q and the average Nusselt number Nuk on each tube. The conservation equations of the air outside and inside the hot box and the heat conduction equation of the hot box walls are also solved by coupling. Then, in order to select a suitable flow model, a comparison of the root mean square errors between the CFD results of temperature obtained from all selected flow models and the experimental data is required. Significant FindingsThe significant findings are that the RNG k-ε model is selected as the appropriate flow model for this study through the validation tests of various flow models. The vortex ring appears in the central low-velocity region of the four tubes with StD=2 and gradually disappears with the decrease of StD. The two thermal plumes above the upper two tubes with StD=4/3 are slightly inclined inward and merge with each other. But these two plumes above the upper tubes are inclined slightly outward as StD increases. The obtained velocity patterns and Nuk agree with the interferometric images and the modified correlation, respectively.

Laboratory Testing and Theoretical Modeling of Deformations of Reinforced Soil Wall

This paper presents the results of an experimental investigation of a vertical reinforced soil (RS) wall. The structure was built on a laboratory scale. Horizontal displacements on the surface of the model wall were monitored at the end of construction and during surcharge application (as post-construction displacements). The experimental results were compared with their theoretical predictions. The accuracy of the selected analytical approach was examined to predict deformations of the RS structure under external loading. It was shown that the proposed original and relatively simple analytical method for estimating structural deformation can be successfully used in practice (the average difference between the recorded and calculated values of deformation did not exceed 25%). From a scientific point of view, an important element of this work was the analysis of the effect of friction between the backfill and the side walls of the test box on the measured displacements. For the investigated case, it was shown that the impact of this element caused a reduction in the value of external loading of more than 60%. The final results may be particularly useful in the design process of structures used in transportation engineering (bridge abutments), where deformation limit values cannot be exceeded.

Medium-scale laboratory investigation of the effect of confinement on ice rubble strength and failure behavior

Understanding the deformation and strength of ice rubble is key to estimating ice ridge loads on ships, offshore structures and subsea infrastructure. Medium-scale punch tests were conducted at C-CORE's Cold Room facility to measure and observe the strength and failure behavior of freshwater ice rubble. A custom-built punch box measuring 3.05 m in length and 0.94 m in width and height was used to perform the tests. The box walls were made from Plexiglas so that failure mechanisms could be observed. Ice rubble beams of nominal thickness 50 cm were produced by placing randomly sized ice pieces into the punch box, filled with water at its freezing temperature. Beams were left for a period of 4 h to consolidate under vertical confining pressures ranging from 0 kPa to 40 kPa. The ice rubble beam was deformed by pushing a platen vertically downwards though the center of the beam until failure. Results showed that the failure behavior of the ice rubble beam was controlled by the degree of freeze-bonding/sintering between the blocks, which significantly increases with applied confinement.

Numerical Analysis of the Impact of Geometric Parameters of the Outcuts in the Wing Torsion Box Wall on the Mechanical Properties of the Structure

Numerical Analysis of the Impact of Geometric Parameters of the Outcuts in the Wing Torsion Box Wall on the Mechanical Properties of the Structure

Effect of Core Geometry, Orientation and Support on the Core Shift in Mould

Abstract: This paper focuses on how to improve the effect of core geometry and its orientation when core shift occurs in the mould. Core shift is the change in position of the core from its original position in the mould before the molten fluid is passed into the cavity. Core shift occurs due to the temperature difference in the mould box and the pressure induced on the side walls of the mould box. Thus, the final product will have unexpected and uncountable variations and defects which will have a huge impact on the mechanical properties which in turn will affect the performance when running an operation. Also, the design and analysis of the final product will give an estimation on the various stresses acting on the core and how it will eventually affect both the mould and the core during the casting process. The problem of core shift has been resolved and the results obtained from the correction, have made an impact on the small foundries which usually do not operate in a systematic way. Thus, the goal of minimal to absolutely zero core shift can be achieved and the new final product will have more advantages compared to the old product with defects. Keywords: Core shift, Cavity, Knuckle joint, Fork end, Sand casting, Core, Mould.

A new practical method for the flexural analysis of thin-walled symmetric cross-section box girders considering shear effect

This study proposes a new analytical flexure theory that considers the shear deformation of the web and flange of a thin-walled box girder. Starting with the relationship between the strain and displacement of each slab, the flexural displacement function of thin-walled box girders considering the shear deformation effect is derived by using the deformation continuity condition. Compared with the traditional flexural displacement model, this function obtained by the theoretical analysis is more rigorous and can be transformed into the flexural displacement function of the traditional shear lag or Timoshenko beam by eliminating some parameters. Then, according to the balance conditions of axial force and bending moment, the shear deflection deformation state and Euler–Bernoulli beam deflection deformation state are decoupled. On this basis, a new convenient method for calculating the warping stress and shear deflection of thin-walled girders is proposed. Furthermore, a simplified analysis method for converting continuous box girders into simply supported beams is proposed on the basis of continuity condition of shear deflection at middle supports. Taking into account the shear deflection deformation state, a beam-type finite element model considering the shear deformations of each box wall is developed by using Hermite polynomials to analyze the complex variable cross-section box girder. Finally, numerical examples are used to verify the effectiveness of the simplified method and the beam-type finite element model. Numerical examples show that the flexural stress and deflection calculated by the proposed method agree well with the three-dimensional finite element model analysis results. The shear warping normal stress has a larger value at the shear force discontinuity point. In the control cross-section, the normal warping stress and shear deflection caused by shear deformation both exceed 75% and 38% of stress and deflection of the Euler–Bernoulli beam, respectively.

Curding of milk in incubator utilizing latent heat of lauric acid in winter

AbstractThe maintenance of incubation temperature (30°C‐50°C) for growth of culture is essential during fermentation of milk to curd. This report discusses the issue of maintaining constant temperature of milk for formation of curd using lauric acid (m.p. 45.02°C and f.p. 40.21°C) as phase change material (PCM). Lauric acid possesses phase transition enthalpy, 189.43 kJ kg−1 and was thermally stable till 140°C. A known dimension of a temperature controlling packaging (TCP) box was made by taking 240 g of PCM uniformly distributed inside six polyethylene packets (40 g each) of dimensions identical with that of inner walls of the corrugated box and the packets were placed along inner walls of TCP box. The TCP box containing packets with molten PCM could maintain the temperature of 150 g milk (placed inside box) in between 50°C and 30°C for 160 minutes and helped in curd formation, while the whole assembly was exposed to 1°C of ambient temperature.

Mechanism of Thermal Protein Aggregation: Experiments and Molecular Dynamics Simulations on the High-Temperature Behavior of Myoglobin.

Proteins that encounter unfavorable solvent conditions are prone to aggregation, a phenomenon that remains poorly understood. This work focuses on myoglobin (Mb) as a model protein. Upon heating, Mb produces amorphous aggregates. Thermal unfolding experiments at low concentration (where aggregation is negligible), along with centrifugation assays, imply that Mb aggregation proceeds via globally unfolded conformers. This contrasts studies on other proteins that emphasized the role of partially folded structures as aggregate precursors. Molecular dynamics (MD) simulations were performed to gain insights into the mechanism by which heat-unfolded Mb molecules associate with one another. A prerequisite for these simulations was the development of a method for generating monomeric starting structures. Periodic boundary condition artifacts necessitated the implementation of a partially immobilized water layer lining the walls of the simulation box. Aggregation simulations were performed at 370 K to track the assembly of monomeric Mb into pentameric species. Binding events were preceded by multiple unsuccessful encounters. Even after association, protein-protein contacts remained in flux. Binding was mediated by hydrophobic contacts, along with salt bridges that involved hydrophobically embedded Lys residues. Overall, this work illustrates that atomistic MD simulations are well suited for garnering insights into protein aggregation mechanisms.

Harmonic Analyses of Hydrodynamic Characteristics for Gap Resonance Between Fixed Box and Vertical Wall

Two marine structures arranged side by side with a narrow gap may suffer from violent free-surface resonance, which would cause green water on deck, dramatically raise hydrodynamic loads on structures and seriously threaten the operation safety. The CFD-based open-sourced software, OpenFOAM®, is employed to simulate the two-dimensional fluid resonance inside a narrow gap between a fixed box and a vertical wall induced by regular waves with different wave heights. The topographies with various plane slopes are placed in front of the wall. The focus of this article is on the influences of the incident wave height and the topographic slope on the nonlinear characteristics of various hydrodynamic parameters (including the wave height in the gap, the vertical wave force, and the horizontal wave force on the box) during gap resonance. The ratios of their high-order to the corresponding 1st-order components under different sets of the incident wave height and the topographic slope are analyzed. It is found that the relative importance of all the high-order components increases gradually with the incident wave height for all the three parameters. The topographic influence on them closely depends on the type of the parameters and the incident wave height. In addition, the occurrence of the 2nd-order gap resonance phenomenon can cause the 2nd-order wave height and horizontal force to be significantly larger than the corresponding 1st-order components.

Manajemen Low Flow Anesthesia pada Pasien Kraniosinostosis dengan Hipertelorisme yang menjalani Four Box Wall Osteotomy, dan Eksisi Redundant Skin Fronto Nasal

Craniosynostosis is a case that diagnosed in the first year of life and can need surgical in young age. Craniosynostosis is a part of hypertelorism with incidence rate around 20%. Boy, 13 years old with hypertelorism had undergone multiple surgery for correction of hypertelorism before. Patient was planned to advance surgical correction of four box wall osteotomy which consist frontal part correction and part of it is release craniosynostosis in coronal suture. Risk of massive bleeding because patient already in teen age and length of surgery can be prolonged. Difficult airway management due to fascial deformity, use of low flow anesthesia to preserve temperature and reduce inhalation anesthesia usage, intraoperative fluid management in consideration maintenance and replacement blood loss and post operative pain management has become another consideration. Covid-19 as part of problems post operatively being known before extubation made the process is delayed. Massive bleeding needs massive transfusion protocol to speed up blood availability. Blood product such as PRC, FFP and TC should be available because coagulation factor is part of consideration. Anesthesia management in hypertelorism with four box wall osteotomy need good communication between anesthesiologist, neurosurgeon, plastic surgeon and pediatric intensivist to reduce perioperative risk including covid-19 in pandemic era.

Modelling of density of states and energy level of chalcogenide quantum dots

AbstractQuantum dots (QDs) or semiconductor nanocrystals are luminous materials with unique optical properties that can be fine-tuned by varying the size of the material. Chalcogenide QDs show strong quantum confinements effects owing to the fact that the exciton Bohr radius is much larger than the particle size, and tunable energy bandgap leads to widespread technological interest in near-infrared optical devices. In this communication, one dimensional Cu2SnS3and PbSexS1-xQDs is modeled by a particle in a box model which was used to compute energies and density of states. The density of states and the energy level of QDs are determined as a function of the strengths of the potential walls of the inner box. The results exhibit that the density of states decreases exponentially with an increase in the energy level of QDs. The density of states at lower energy levels is more significant than what is observed in higher energy levels.