Room Dimensions Research Articles

Sensitivity analysis of damage extent in naval ship compartments due to internal airborne explosions

The objective of this paper is to identify the design variables of the compartment that are most influential in determining the extent of damage due to in-compartment airborne explosions (INCEX). From a comparison of numerical simulation results using the CONventional Weapons Effects Program (CONWEP) with results from airborne blast experiments, CONWEP generated blast pressures with reasonable accuracy. From a comparison of numerical simulation results using the Horsford-Coulomb and local necking hybrid fracture model (HC-LN model) with results from indentation experiments, HC-LN model accurately predicts steel fractures. The engine compartment was selected for the damage variable sensitivity analyses in terms of the probabilities of being hit, flooded, and incapacitated. When three TNT masses, two stand-off distances, and eight engine room dimensions with six levels of each dimension were considered, more than 10 million INCEX cases were required. The Latin hypercube sampling technique was adopted to reduce the number of INCEX simulations to 5,000. The element-based and image-based methods were applied to evaluate the damage extents. The element-based method underestimated and overestimated the damage area and damage perimeter more than the image-based method, respectively. The most influential design variables on the damage extent were bulkhead thickness and curtain plate height, respectively.

Blast wave ingress into a room through an opening – Review of past research and US DoD UFC 3-340-02

Blast wave ingress into a room through a facade opening results in complex pressure-time loadings on interior surfaces due to shock diffraction and interior reflections. The U.S. DoD UFC 3-340-02 Structures to Resist the Effects of Accidental Explosions includes a method to predict internal loading for such cases. Parameters such as the opening size, room dimensions and the external pressure wave characteristics influence the interior loading. Recent work suggests that the UFC methodology might overpredict the interior loading by some 600%. Such conservatism can result in over-engineered or prohibitively expensive protective solutions. In this paper we critically review the methodology of the UFC, that of Kaplan’s preceding work (on which the UFC relies), and the experimental data that informed both these works. Through a series of 45 case-studies we compare the UFC and Kaplan’s predictions with those of a computational fluid dynamics (CFD) model. The UFC consistently overpredicts the CFD area-averaged peak pressure of the back wall by up to 290% and the side-wall by up to 425%. Similarly, the UFC overpredicted the CFD side wall positive phase impulse by up to 565%. By contrast, the UFC predicted back wall positive phase impulse was similar to the CFD results. As our CFD results for side and back walls are area averaged, and not solely for the wall centre-point, as in other recent work, our paper gives support for the use of CFD prediction over the UFC for cost-effective design of structures to resist blast ingress.

A revised online tool for room acoustic prediction of open-plan offices

Room acoustic conditions in open-plan offices are usually measured using ISO 3382-3 standard. The essential single-number quantities obtained from the measurement are comfort distance and distraction distance. Their values can also be predicted using a regression model of Keränen & Hongisto (2013). The prediction accuracy of the model has been proven to be high. The input variables for the model are simple to obtain: room dimensions, screen height, ceiling absorption, vertical absorption, speech level, and background noise level. The prediction model was published online in 2008 but withdrawn in 2013. Since then, we have been repeatedly asked to return the online tool. Since the standard was updated in 2022, we developed a revised online tool that predicts the single-number values of ISO 3382-3 standard. The purpose of this study is to present the online tool and validate its reliability by comparing online tool results to previously published results. The comparison shows that the online tool results agree with the above-mentioned studies. Therefore, the online tool can be safely used. It is a valuable aid in workplace design, demonstrations, research, and education.

Variability of low frequency laboratory measurements of acoustic isolation of floor/ceiling assemblies

It has long been recognized that building acoustics measurements performed in laboratories exhibit a high degree of variability between and within labs. Traditional metrics limited the use of data to above the 100Hz or 125Hz one-third octave bands. In recent years, focus has widened the range of frequencies of interest to the 50Hz one-third octave band or lower. Analyzing measurements of low frequencies in buildings is complicated by the physical reality of wavelengths that are similar in scale to common room dimensions resulting in modal behavior and the mathematical simplification of the wave equation in building acoustic calculations that assumes a diffuse field which discounts both phase and angle of incidence. Evaluation of common building isolation measurements of the same test floor/ceiling structure sample in the same lab and between labs across the frequency spectrum allows the comparison of the repeatability and reproducibility at low frequency ranges to those at high frequency ranges. Measurements and their associated metrics of various sources, including pink noise produced by loudspeakers, the standard tapping machine, and the impact ball are included in the analysis.

Evaluation of insulation effectiveness for thermal comfort in summers: experimental and CFD numerical study

We evaluate the thermal performance of PUF-insulation boards embedded in the roof of an office-sized room. Two rooms were constructed: one with and the other without insulation. The thermal comfort was evaluated by performing an experimental study according to ANSI/ASHRAE Standard 55-2017. The inside air temperature, humidity, wall and ceiling temperatures, air velocities and thermal flux were measured for the summer April–June 2023. Using these measurements, the PMV and PPD values were computed. The effectiveness of the insulation material with regard to thermal comfort is judged by the reduction in values of these indices. During a typical day, a reduction of around 30% is achieved just by adding the insulation. Nusselt number correlations are proposed to predict the convective heat transfer from the walls. Detailed CFD simulations were performed and a parametric study to understand the effect of insulation thickness, wall insulation, roof thickness and room dimensions on thermal comfort was undertaken.

Experimental study on the effect of light source arrangements on the disinfection performance of upper-room 222 nm Far-UVC

The air disinfection efficacy of upper-room 222 nm Far-UVC was experimentally investigated in a real-size chamber under well-mixed air conditions. Two bacteria (Escherichia coli, Staphylococcus epidermidis) and two bacteriophages (MS2, and P22) were selected for the test. The study considered different lamp source arrangements, including single and double sources, stationary and rotating operating modes, and an overlapping mode with a 45° irradiation angle. A numerical view-factor model was developed to analyze the irradiance distributions. Four irradiation angles, 30°, 45°, 60°, and 90°, were chosen. The results show that the lamps operating with an irradiation angle of 45° provide the highest chamber-averaged irradiance. This suggests an optimal irradiance level for a given room dimension, as inferred from the view factor model. Experimental results indicated that the overlapping mode with a 45° irradiation angle consistently outperformed both the stationary mode and rotating mode in disinfection. This can be attributed to the higher chamber-averaged irradiance, which is also supported by the numerical model predictions. The increment ratios ranged from 14.9 % to 42.9 % compared to the stationary mode. The susceptibility constants of Escherichia coli, Staphylococcus epidermidis, MS2, and P22 were measured as 0.572 m2/J, 0.099 m2/J, 0.060 m2/J, and 0.081 m2/J respectively.

Analysis of 3D positioning error for multipath indoor VLC system

SummaryA comparative analysis of 3D positioning error for two different configurations using different layouts of visible light communication (VLC) systems is presented in this paper. The Received Signal Strength (RSS) has been implemented for indoor localization systems using Line‐of‐Sight (LoS) and diffused reflection signals. The room size for configuration‐1 is 5 m × 5 m × 3 m, and the distance between adjacent LEDs is 2.5 m, 2.00 m, and 1.5 m for cases‐1, case‐2, and case‐3, respectively, whereas the room size for configuration‐2 is 7 m × 7 m × 5 m, and the separation between the LEDs is 3.5 m, 3 m, and 2.5 m for their respective cases. Through investigation, it has been shown that when only LS signal is considered, the separation between LEDs may not be an issue because positioning error changes by a very small amount as the separation between LEDs changes. The results show that as the distance between adjacent LEDs decreases, the received signal strength for LoS and L‐R1 signals increases. However, positioning error and BER rise, while the bit rate falls. Furthermore, the positioning error Vs receiver plane height for all three cases in configuration‐1 is the same up to a height of 2.89 m, whereas the positioning error in configuration‐2 is the same up to 4.4 m for all cases. The positioning error for case‐1 decreases as the height in configuration‐1 exceeds 2.89 m. Similarly, after reaching a height of 4.4 m for case‐2, the positioning error in configuration‐2 decreases. The LoS positioning error versus semi angle of the LED as well as the FOV of the receiver has been simulated for different positions of the receiver in configuration‐1. The investigation shows that the minimum positioning error is achieved at and FOV equal to 66.660 for all the positions of the receiver in the room. Thus, before configuring a practical indoor VLC geometrical model, proper VLC configurations such as LED separation, FOV of the receiver, semi angle of LED, and receiver height should be chosen based on the room dimensions.

The impact of audience dynamics on public speaking anxiety in virtual scenarios: An online survey

BackgroundPublic speaking is one of the most commonly feared situations reported in both community and university samples. Despite extensive theoretical models and empirical studies aimed at delineating the underlying factors of Public Speaking Anxiety (PSA), the specific variables contributing to its onset remain incompletely characterised. MethodsThe research involved 297 participants from an AmazonTurk survey, engaging with virtual public speaking scenarios differentiated by audience size, engagement levels, and room spatial dimensions. Participants' anticipated anxiety levels were quantitatively assessed across these scenarios, enabling a comprehensive exploration of the interaction between situational variables and PSA, thereby providing a framework to explore the influence of audience size, engagement, and spatial dimensions on PSA. ResultsThe mixed-effect model revealed a significant interaction among audience size, audience engagement, and room spatial dimensions. Further analyses using principal axis factoring and multiple regression identified three main factors: F1 (Engagement in a Large Audience), F2 (Confinement or Evaluation Anxiety), and F3 (Audience Disengagement). These factors significantly predict PSA scores. ConclusionsThis study reveals that PSA is influenced by a complex interplay of audience size, room dimensions, and audience engagement. The finding underscores the viable way to incorporate these situational variables in both empirical investigations and therapeutic interventions. Specifically, it introduces a novel framework for standardising audience size relative to room capacity.

Sound absorption uncertainty in small reverberation chambers

Manufacturers in the mobility industry typically measure and specify the sound absorption coefficient of materials using a small reverberation chamber according to SAE J2883. These chambers have a 6 to 25 cubic meter volume, use a 1.0 meter x 1.2 meter sample size and report sound absorption in the one-third octave bands from about 400 Hz to 10,000 Hz. This is in contrast to a full-size chamber built to satisfy the requirements of ASTM C423 or ISO 354, which have about a 200 cubic meter volume, use a 2.4 x 2.7 or 3.2 x 3.2 square meter sample size and report sound absorption in one-third octave bands from 100 to 5,000 Hz. Although the room and sample size dimensions scale, many of the factors that contribute to uncertainty in the measurement do not scale. These include relative humidity, temperature, and other physical measurements and if the same instrumentation is used, microphone calibration and measurement uncertainty in the higher frequency range. This paper examines the potential measurement uncertainty in these chambers over the 400 to 10,000 Hz frequency range and compares this to past uncertainty analyses of full-size chambers over a similar frequency range.

Innovative technology for mining parallel superimposed inclined tabular deposits

Ore deposits are often parallel superimposed inclined tabular ones with waste rock inclusions between ore beds. The present research aims to develop an innovative safe and efficient technology to reduce the cost of waste rock transportation outside the stoping block and provide a rational flowsheet for mining superimposed beds with original structural elements. The paper proposes a new technological flowsheet for mining superimposed deposits with disposal of waste rocks occurring between beds in previously prepared rooms and establishes new dependencies of room dimensions on the volume of rocks to be disposed. The research results enable expansion of the scope of employment of room mining systems and significant reduction in costs in the working area. The efficiency of ore mining is achieved by creating room crowns from unmined interbedded rocks, disposing broken waste rocks in worked-out spaces and rationally mining the deposits. Implementation of the proposed technology enables reduction of the cost of mining ore from parallel superimposed inclined tabular deposits.

Efficient three-dimensional indoor dark light visible light positioning with received signal strength technique

A unidirectional Visible Light Communication (VLC) system has the potential to serve as an Indoor Positioning System (IPS). However, it is important to note that many existing VLC IPS setups rely on keeping LED lights switched on, which can lead to energy wastage when indoor lighting is unnecessary during daylight hours. Additionally, most indoor Visible Light Positioning (VLP) research has focused on 2D localization, assuming a fixed receiver height. This approach tends to overlook the positional inaccuracies that can arise due to variations in height. In this paper, to address these concerns, a 3D IPS is proposed. This system employs multiple transmitters and a single receiver, utilizing a Dark Light Visible Light Communication (DL-VLC) system. This innovative approach ensures the functionality of IPSs even when LEDs are turned "OFF" resulting in more efficient energy usage. The results of the investigation indicate that the positioning error remains within approximately 3 cm when the receiver is positioned at a height of 2.4 m, assuming standard room dimensions, which is in a fair agreement with previously published work.

Assessment of Residential Satisfaction using Gap Analysis: A Case Study in Naypyitaw City, Myanmar

This research paper conducts an evaluation of residential satisfaction within government-provided four-storied apartment complexes situated in civil-servant housing areas in Naypyitaw City, Myanmar. As the construction of these apartment buildings continues to address the housing demands of civil servants, comprehending the determinants of residents' contentment becomes paramount. The study encompasses data collected from 500 households through structured questionnaires employing a multi-cluster sampling approach. These questionnaires utilize a five-point Likert Scale format to gauge residents' levels of importance and satisfaction. Gap Analysis is employed to scrutinize the gathered data, ultimately identifying seven pivotal attributes that hold the potential to substantially enhance residential satisfaction. These attributes encompass ceiling height, apartment layout plan, room and corridor dimensions, quantity of rooms, staircase design, neighborhood relations, and proximity to police stations. Based on these revelations, recommendations are tendered, advocating the modification and reevaluation of these attributes in forthcoming housing developments. This underscores the imperative need for creating a livable city by ensuring the provision of essential services in closed proximity to residential areas.

The Lifestyles of Space Standards: Concepts and Design Problems

Space standards are envisioned as a powerful means to regulate dwelling design, ensuring the quality, functionality, and safety of homes. Their ultimate objective is to guarantee a minimum level of design quality that can accommodate a wide range of domestic activities. While space standards primarily focus on isolated quantitative aspects such as overall size, room dimensions, and occupancy limits, they also make assumptions about activities to be performed by ideal “users” and specific lifestyles to be accommodated within a home. However, these assumptions are being challenged by the increasing demands and diverse activities taking place in the dwelling realm, which call into question the validity of existing space standards. In response to these challenges, this article conducts a critical review of the theoretical basis and various interpretations of space standards, particularly in the context of England. It explores their fundamental concepts and historical approaches, as well as examines specific examples of their application and their correlation with design strategies. By delving into the concepts of “the normal” and “the minimum dwelling,” the article discusses the three main dimensions of space standards: program, user, and size. Consequently, it argues for a more comprehensive understanding of the general application of space standards, which requires incorporating architectural design problems, particularly from the perspective of flexibility. This approach takes into account the evolving needs and diversity of households, as well as the creation of inclusive and adaptable living spaces.

Comparison of reverberation times and average absorption coefficients in classrooms, based on in situ measurements versus calculated from material databases as during design

Reverberation time (RT) is an acoustic descriptor used widely by acousticians for characterizing indoor acoustic environments, as specified in standards such as ANSI S12.60 “Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools”. It is often calculated in the design phase for simple spaces by applying equations like Sabine’s or Eyring’s, requiring information on room dimensions and the surface areas and acoustic absorption coefficients across frequency of room materials. In this project, measured RTs from a recent survey of over 200 K-12 classrooms are compared against the RTs predicted across speech frequency octave bands using Sabine’s and Eyring’s equations. Agreement between predicted and measured values varies based on the octave band and material selection. The working group currently revising ANSI S12.60 is considering providing guidance on the desired average absorption coefficient in classrooms, rather than reverberation time, so this study also compares the average absorption coefficients for the classrooms. The coefficients are back-calculated from the measured RTs using Sabine’s and Eyring’s equations, and compared against those calculated from surface dimensions and commonly available material absorption coefficients.

Design of Rotary Motor Wiring Diagram for Tugboat Ship Maneuvering System Using Cam Switch Control

The maneuverability of tugboats is very necessary for narrow turning areas, so many tugboat maneuvering systems use motors which are currently applied with cam switches. It is important to plan a wiring system to anticipate disruptions to distribution electricity. Therefore, the electricity supply for the equipment can be met and run as expected. The aim of this research is to obtain rotary motor wiring diagram system for tugboat ship maneuvering system using cam switch control. The R&D (Research and Development) method combined with experiments was carried out to obtain an ideal rotary motor wiring diagram system based on the dimensions of the tugboat's engine room. In forward rotation for this motor is a decrease before stabilization occurs, the voltage is 18% meanwhile, reverse rotation experienced a decrease of 32%. This difference with motor if workload which is charged which also experiences variations, for forward rotation the increase is 48%, also for reverse rotation it is 43%.

‘The window area shall be at least one-tenth of the area of the room’: The origins of a daylight (and ventilation) requirement in modern building codes

Current New Zealand (New Zealand Building Code), Australian (National Construction Code) and American (International Building Code) building codes include deemed-to-satisfy requirements for a given proportion of a house’s floor area (e.g. 10%) to be in windows. These, plus the current English Building Regulations, also require a proportion of windows to be openable (e.g. one-half or 5% of the floor area). A detailed summary table supported by code extracts is used to trace the evolution of these requirements. Even the architects of antiquity provided only rules for window proportions but not for window area or size based on room dimensions. The paper demonstrates the evolution of this 21st century requirement follows a direct line to the English 1859 model ‘ Byelaws as to New Streets and Buildings’. Prior to that date, only two rules from 1842 (room volume based) and 1734 (height and volume based) have been found which gave a required window area based on room size. It is hypothesised that one of these led to the current rules. Although the current proportion rules may be appropriate, no empirical research-based origin has been identified.

Generic geometrical parametric study of wind-driven natural ventilation to improve indoor air quality and air exchange in offices

Indoor air quality significantly enhances employee productivity and well-being in offices. Existing models and guidelines emphasize wind-driven natural ventilation for air exchange and thermal comfort but often overlook detailed airflow patterns. Understanding airflow dynamics is crucial for designing healthy offices, and offering insights into air exchange processes. This information is particularly valuable in mitigating the impact of CO2 and droplet release from multiple occupants, contributing to the creation of healthier office environments. This study, thus, employs a validated CFD model to investigate the impact of geometrical parameters on wind-driven ventilation in offices. With about 150 cases representing alterations in parameters for single-sided (SV) and double-sided (DV) ventilation, a sensitivity analysis identifies key contributors to airflow patterns. Eventually, while five major categories for the airflow patterns can be identified in the DV cases (i.e., (1) without a weak zone (WZ), (2) with a dominant WZ, (3) with a WZ on bottom side, (4) with a WZ on upper side, and (5) with two WZs on upper and bottom sides), a generic airflow pattern can be barely seen in the SV cases. Moreover, in the DV cases, velocity magnitude is crucial for classification of the outputs. The leeward window geometry influences DV natural ventilation more than the windward window. Furthermore, the room dimensions impact ACH more than SF6 concentration and velocity. In the SV cases, location of the infected occupant dominates air changes per hour (ACH), and theta significantly impacts average velocity in contrast to the DV scenarios.

Design of the electrical system on a general cargo ship with a length of 105,669 meters

This research investigates the incorporation of LED lights and the zonal cavity method in the initial design stage of a cargo-type ship, focusing on efficient lighting for diverse ship zones. The study aims to determine optimal lighting requirements, adhering to industry standards, for zones such as double bottom, maindeck, poopdeck, boatdeck, bridgedeck, navdeck, and emergency conditions. Ships play a vital role in transporting passengers and goods across seas and rivers, necessitating effective lighting systems for safe operations, particularly during nighttime. This paper explores the integration of LED lights and the zonal cavity method in the general arrangement design of a cargo ship. The zonal cavity method is applied to ascertain lighting intensity in different ship zones based on room dimensions, including width, height, length, and area. Illumination values are determined according to established standards for each zone. The cumulative lighting electricity load for various ship zones using LED lights is calculated to identify specific power requirements.The lighting power requirements for the double bottom, maindeck, poopdeck, boatdeck, bridgedeck, navdeck, and emergency conditions are found to be 0.141 KW, 0.75 KW, 1.068 KW, 0.762 KW, 0.671 KW, 0.42 KW, and 0.296 KW, respectively. The total lighting power for all zones is calculated as 3.7776 KW, suggesting the installation of a 4 KW generator for optimal power supply.The application of the zonal cavity method in the planning and design of a cargo ship's lighting system, combined with energy-efficient LED lights, proves to be an effective approach. The results indicate that a 4 KW generator is sufficient to meet the lighting power demands for various ship zones, ensuring compliance with safety standards and technological advancements in maritime lighting.

Digital Twin Technology in Data Center Simulations: Evaluating the Feasibility of a Former Mine Site

Mining activities often deem mine sites as temporary, leading to their eventual reclamation, rehabilitation, or abandonment. This study innovates by proposing the re-purposing of the disused Osarizawa mine in Akita, Japan, leveraging its consistently low tunnel temperatures to establish a data center, thereby offering a sustainable economic avenue to offset reclamation costs. We assessed the feasibility of this transformation by gathering comprehensive environmental data from the site and conducting meticulous ventilation simulations. These simulations explored various scenarios encompassing diverse ventilation configurations, data server room dimensions, thermal outputs, and the inherent cooling capabilities of the proposed humid rooms. By juxtaposing the simulation outcomes with the criteria set forth in the ASHRAE 2011 Thermal Guidelines, we pinpointed the optimal parameters that satisfy the stringent temperature and relative humidity prerequisites essential for a data center’s operation. This research underscores the potential of reimagining abandoned mine sites as strategic assets, providing economic benefits while adhering to critical data center infrastructure standards.

PLANNING FOR THE CONSTRUCTION OF SPECIAL WAITING ROOM FACILITIES FOR PEOPLE WITH DISABILITIES AT TERMINAL 1 OF JUANDA AIRPORT SURABAYA

Airports are key gateways for global mobility and are important for all passengers, including those with special needs, such as passengers with disabilities. In an effort to improve services to passengers with disabilities, planning inclusive and disability-friendly facilities is a must. This research uses descriptive analysis method. This research aims to design and plan waiting room facilities that meet the needs and provide a better experience for disabled passengers at Juanda Airport. Data collection techniques by taking data from the source where the problem occurs by observing the existing conditions in Terminal 1 of Juanda Airport Surabaya and recording the absence of a disabled waiting room and interviewing Landside employees of Juanda Airport Surabaya regarding the absence of a disabled waiting room. The design contained in this waiting room provides supporting facilities such as chairs with foldable arms, information boards with large letters, clear and current announcement systems, and hearing aids. Based on the planning results, the design of the disabled waiting room facility plan is obtained in accordance with the author's guidelines using Autocad and Sketchup with room dimensions of 7.5 meters x 4 meters. To support the manufacture of waiting room facilities at Terminal 1 Juanda Airport Surabaya, the RAB calculation using Microsoft Excel was obtained at Rp. 207. 571. 000 ,00 spelled out two hundred and seven million five hundred and seventy-one thousand rupiah