Type Of Construction Research Articles

Material Characteristics of Compressed Dry Masonry Made of Medium-Size Elements with Perlite Aggregate

Dry masonry is a type of construction that is nowadays used to a limited extent in the construction sector, including the housing sector. A lack of codified computational methods enabling engineers to design consciously is one of the factors limiting the development of dry walls. This article presents results from testing an innovative solution for dry masonry made of medium-size elements with expanded perlite aggregate. Material with this type of aggregate has a low bulk density (390 ± 10% kg/m3), which allows the production of large blocks and significantly reduces the value of the thermal conductivity coefficient λ = 0.084 ± 0.003 W/m·K. The results obtained were used to determine material parameters for designing a structure mainly exposed to vertical load. The important practical significance of the presented research results from the lack of provisions, specifications or standards allowing for the design, calculation and construction of dry masonry; it is not possible to analyse the behaviour of this type of structure and to design it consciously and safely. The presented research is therefore an important source of information on mechanical parameters essential for the design of structures and provides tools for this. As a result of the tests of nine panels, the mean compressive strength was determined (1.085 N/mm2), and then the procedure of “design assisted by testing” implemented into Eurocode was used to determine characteristic (0.873 N/mm2) and design compressive strength (0.565 N/mm2). Using the relationships σ-ε, an attempt was made to identify material models for the linear and non-linear analysis of the structure and for designing cross-sections. The material models were made considering increased non-linear deformations of a structure under low stresses (the compression toe) which are true and typical for dry masonry. A specific deformability of dry masonry, slightly different to that in masonry structures joined together with mortar, also affects the reduction factor for load-bearing capacity due to second-order effects. Reduction factors determined from true non-linear deformations were lower than the values specified by EC6 for masonry structures.

Fire in house - investigation of the outbreak and spread of the fire in a countryside house

Fire in houses are a significant hazard often resulting in loss of life and substantial repair costs due to damage to the structure and contents. There is a clear need to prevent its ignition and spread to adjacent areas. This article presents the steps taken, namely: contacts, data collection, tests, analysis, and conclusions regarding the accident resulting from the outbreak and spread of a fire, on December 25, 2020, in a traditional Portuguese house in Arganil, Portugal. An expert with specialized technical-scientific knowledge was requested to conduct this investigation, which involved observations and data analysis followed by laboratory tests the work consists of carrying out observations and data analysis. Then, the observed and analysed data were laboratory tested to consistently identify characteristics that lead to the ignition and propagation of the fire. This work identified construction problems, materials used and heat sources that are responsible for the accident. The conclusions may be used to avoid future incidents or accidents with houses of same construction type.

Data Classification System for Economic Analysis after the Implementation of Separate Order Construction in the Firefighting System Installation Business

Data on the performance of the firefighting system installation business are scarce compared with other construction projects, such as electricity and information and communication projects, where separate order construction was previously practiced. This study aimed to obtain data on fire facility construction contracts by analyzing the current data, deriving improvement plans, and reviewing empirical studies on separate order construction from various construction projects, both domestically and internationally. An analysis of the data from Statistics Korea and the Public Procurement Service revealed an annual increase in the number and amount of firefighting system installation projects. In addition, the scale of the construction could be identified using separate order construction data. This study highlights cost reduction, shortened construction delay periods, and increased construction speed as the key economic review items. Based on these findings, a data classification system for the construction of firefighting facilities was proposed and categorized according to the project size, ordering organization, contractor, type of construction, construction period, and contract method.

Second Life for Recycled Concrete and Other Construction and Demolition Waste in Mortars for Masonry: Full Scope of Material Properties, Performance, and Environmental Aspects

This review presents the scope of current efforts to utilize recycled construction and demolition waste in mortars for masonry. More than 100 articles are divided into groups pertaining to the type of mortar, different binder systems, the type of construction and demolition waste (CDW), and its utilization specifics. Cement-based mortars dominate this research domain, whereas recycled concrete is the main material employed to replace virgin aggregates, followed by recycled masonry and recycled mixed waste aggregates. Such application in cement-based mortars could increase water demand by 20–34% and reduce strength by 11–50%, with recycled concrete aggregates being the most favorable. Natural aggregate substitution is disadvantageous in strong mortars, whereas weaker ones, such as lime-based mortars, could benefit from this incorporation. The extent of this topic also suggests possibilities for different recycled material use cases in mortars for masonry, although the available literature is largely insufficient to infer meaningful trends. Nonetheless, the most relevant knowledge synthesized in this review offers promising and environment-conscious utilization pathways for recycled concrete and other construction and demolition waste, which brings opportunities for further research on their use in mortars for masonry and industrial-scale applications.

Simplify to the Limit! Embedding-less Graph Collaborative Filtering for Recommender Systems

The tremendous positive driving effect of Graph Convolutional Network (GCN) and Graph Contrastive Learning (GCL) for recommender systems has become a consensus. GCN encoders are extensively used in recommendation models for capturing high-order connectivities between users and items, whereas GCL accelerates the training of recommendation tasks by adding extra supervision signals from contrastive objectives. However, little attention has been paid on corresponding theories that are truly tailored to recommendation tasks. From the technical perspective, Collaborative Filtering (CF) is seen as an important factor in recommender systems. It is applied to measure user-user, item-item, and user-item similarities rather than to achieve better clustering or node classification results. Besides, heuristic-based data augmentation may not be hold true in the field of recommender systems as it requires additional training costs and introduces noises that will corrupt the interaction graph structure and the semantic information of nodes. To tackle these limitations, we propose a novel Embedding-less Graph Collaborative Filtering (EGCF) for recommendation, which is tailor-made for the problem mentioned for CF and further simplifies existing solutions. Structurally, it consists of two parts: embedding-less GCN and embedding-less GCL. The former improves user-item affinity by streamlining user-type embeddings and carrying out iterative graph convolution. And the latter utilizes three-type contrastive objectives to directly measure the alignment and the uniformity of users, items, and interaction pairs, respectively, avoiding any type of data augmentation or multi-view construction. Even though EGCF has been extremely streamlined, extensive experimental results on three classical datasets demonstrate the effectiveness of EGCF in terms of recommendation accuracy and training efficiency. The code and used datasets are released at https://github.com/BlueGhostYi/ID-GRec.

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.

Extracting efficient exact real number computation from proofs in constructive type theory

Abstract Exact real computation is an alternative to floating-point arithmetic where operations on real numbers are performed exactly, without the introduction of rounding errors. When proving the correctness of an implementation, one can focus solely on the mathematical properties of the problem without thinking about the subtleties of representing real numbers. We propose a new axiomatization of the real numbers in a dependent type theory with the goal of extracting certified exact real computation programs from constructive proofs. Our formalization differs from similar approaches, in that we formalize the reals in a conceptually similar way as some mature implementations of exact real computation. Primitive operations on reals can be extracted directly to the corresponding operations in such an implementation, producing more efficient programs. We particularly focus on the formalization of partial and nondeterministic computation, which is essential in exact real computation. We prove the soundness of our formalization with regards to the standard realizability interpretation from computable analysis and show how to relate our theory to a classical formalization of the reals. We demonstrate the feasibility of our theory by implementing it in the Coq proof assistant and present several natural examples. From the examples we have automatically extracted Haskell programs that use the exact real computation framework AERN for efficiently performing exact operations on real numbers. In experiments, the extracted programs behave similarly to native implementations in AERN in terms of running time and memory usage.

Assessing the Fire Properties of Various Surface Treatments on Timber Components in Ancient Chinese Buildings: A Case Study from the Xianqing Temple in Changzhi, Shanxi, China

Traditional and modern coatings play a key role in enhancing the fire resistance of ancient Chinese buildings. However, further comparative analysis is needed on the fire properties of the two coatings and their effects on different timber structural components. This study focuses on the main hall of the Shanxi Changzhi Xianqing Temple, a typical traditional column and beam construction built between the Song and Jin periods. Firstly, the combustion characteristics of various timber structural component samples with different surface treatments (traditional “Yi-ma-wu-hui” and modern flame retardants) were analyzed using cone calorimeter. Secondly, the fire development process of the Xianqing Temple building model was analyzed by a fire dynamics simulator (FDS), and the effect mechanism of different surface treatments on the burning process was further studied. The results show that the fire resistance of timber structural components is significantly improved after modern and traditional surface treatments. The traditional method is more effective in delaying the peak heat release rate and reducing the surface temperature during combustion, while the modern surface treatment significantly prolongs the ignition time of the timber structural components. The FDS results confirm that modern and traditional surface treatments significantly improve the fire resistance of the building, delaying the flashover time by about 300 s, with no collapse occurring within 800 s. In addition, the fire resistance of buildings after traditional surface treatment is better compared to traditional methods. The above research results can provide direct data support for the selection and optimization of fireproof coatings and treatment methods for ancient buildings.

Economical management of diesel generator sets by means of MATLAB digital technologies

A numerical algorithm for optimizing the technological processes of diesel generator sets operating on various grades of fuel, implemented by means of CVX-technologies, is considered. Traditional algorithms have generally proven to be positive, but can be problematic for optimization due to the large number of variables and the nonlinearity of the model. In addition, due to the huge computational load, they can “stall” or become damaged when used to search for non-standard designs, such as asymmetric D-optimal and large-dimensional spatial structures. It is noted that an alternative to them is calculations in the CVX format, which are widespread and available for solving convex optimization problems. However, their application for the control of technological processes of energy saving in autonomous electric power complexes in transport is still limited. Based on the tools of the CVX package in MATLAB, using their usefulness and flexibility in comparison with traditional optimization methods, this paper proposes technical solutions aimed at developing energy-saving technologies for energy complexes of autonomous systems in the context of digital transformation. The application of energy saving management methods is presented in this study on the example of fuel consumption management by a group of diesel generators with different consumption characteristics of primary engines, for which optimal modes have been obtained at various options of active power consumption by the network. An example of calculating optimal modes in parallel operation of five DGA with CVX program codes is given, confirming the correctness of the proposed solutions. It is shown that the use of CVX programs in MATLAB demonstrates their usefulness and flexibility in comparison with traditional algorithms in the statistics of searching for various types of optimal approximate constructions by convex criterion for nonlinear models.

Field test of internal visualization of deep-water pile foundation using ultrasonic waves

Early-age internal visualization is critical for timely assessing the quality of pile foundations, especially as super cross-sea bridges increase the diameter and length of pile foundations beyond the capabilities of traditional cross-hole sonic logging (CSL). This article introduces two innovations. First, ultrasonic instruments are specially developed to transmit waves through a concrete pile with a diameter of 4 m, a length of 92 m, and a water depth of 63 m, before the full hardening of concrete. Second, an imaging method is proposed to upgrade traditional CSL from 1D detection to 3D visualization. Both large-scale experiments and field tests are tested in the first 7 days after the concrete casting. The experiments successfully visualize typical construction defects, achieving a detection resolution of 18 cm for layered defects and 15 cm for void defects. During the field test, a low-pixel region is observed at the pile head, extending approximately 2.1 m deep, attributed to mud floating up during concrete casting into the steel casing. These developments in instrument technology and visualization methods provide essential tools for the quality evaluation of super pile foundations. Furthermore, the visualization data can support digital twin modeling in subsequent stages of construction and maintenance planning.

Research on the Alternative Model for Personality Disorders (AMPD) in Iran: A Narrative Literature Review

Background: Many original studies have evaluated the validity and utility of the Alternative Model for Personality Disorders (AMPD) in Iran. However, the present review is a unique attempt to summarize the data in a critical framework to cover gaps in the AMPD research and determine future directions. The review aimed to explore the psychometric evidence for the AMPD, including reliability (alpha coefficient) and validity (construct, convergent, criterion, and incremental types) data in Iran. We also reviewed the overlap between the two AMPD criteria and the associations between the constructs and general psychopathology. Methods: We searched PubMed, PsycNet, Google Scholar, and three national databases for English and Persian records related to the AMPD from January 2013 to 2023. Several keywords and criteria were applied to select studies before summarizing the data. Results: The self-report scales were the first-line measures to assess the AMPD constructs, while interviews were rarely used. The research body provided relative support for both the unidimensional nature of Criterion A measures and the five-factor structure of Criterion B measures. Regarding Criterion B, however, there are still questions about the validity of the disinhibition factor and its clinical utility and generalizability. Conclusion: Although a decade of research on the AMPD in Iran has contributed to improving our knowledge, the current review provided a more comprehensive and clear profile of this model’s validity and generalizability to Iranian culture. We discussed the details of validation studies, limitations, and future considerations.

A Machine Learning-Based Algorithm for the Prediction of Eigenfrequencies of Railway Bridges

As part of the development of advanced, data-driven methods for predictive maintenance of railway infrastructure, this paper analyzes and evaluates more realistic predictions of eigenfrequencies of railway bridges, also referred to as natural frequencies, based on a population of already assessed, measured existing bridges using regression techniques. For this purpose, Machine Learning (ML) techniques such as Polynomial Regression (PR), ANN and XGBoost are consistently evaluated and the application of the XGBoost algorithm is identified as the most suitable prediction model for these eigenfrequencies, usable for dynamic train-bridge interactions. The results of the post-processing are incorporated into the safety architecture for bridge verification (risk management). The presented data-based techniques are a steppingstone towards digitalization of structural health monitoring and offer safety and longevity of the railway bridges. Furthermore, the use of these methods can save costs that would be incurred by physical in-situ measurements. The types of bridges analyzed with ML are Filler Beam Bridges (FBE), which outnumber other construction types of bridges in Germany (DB InfraGO AG). This methodology is applicable to any bridge type as long as sufficient data are gathered for training, validation and testing.

The influence of partisan news on climate mitigation support: An investigation into the mediating role of perceived risk and efficacy.

Perceptions of efficacy play a central role in motivating people to engage in climate actions. However, there has been little investigation into how different climate efficacy beliefs are formed and how they may be associated with support for climate mitigation policies. This study, based on the motivated control framework, examines how risk perceptions may differentially be associated with four types of efficacy constructs (self-efficacy, personal outcome expectancy, collective efficacy, and collective outcome efficacy). It also places the motivated control framework in the context of the partisan information sphere and examines how exposure to partisan news may influence mitigation policy support through the mediators of risk perceptions and the efficacy constructs. Results suggest that liberal- and conservative-leaning news exposure, respectively, associate with higher and lower supports for policies. Overall, risk perception was a significant mediator, and the mediating function of efficacy varied depending on the specific construct being examined. For liberal news use, increased risk perceptions had a positive association with policy support through self-efficacy and collective outcome expectancy but also had an unexpected negative association with policy support through personal outcome expectancy and collective efficacy. For conservative news use, decreased risk perceptions resulted in further decreased beliefs of self-efficacy and collective outcome expectancy, resulting in lower levels of support for climate policies. We also find that political ideology is a significant moderator for the mediation model. Implications for climate change communication are discussed.

Kiln–House Isomorphism and Cultural Isomerism in the Pavilions of the Yuci Area: The Xiang-Ming Pavilion as an Example

The pavilion is a time-honored architectural form in the Chinese silhouette with strong regional characteristics. Its appearance and technical means are often adaptively combined according to the characteristics of local architecture. The “kiln–house isomorphism” is a unique construction technology of the Shanxi construction type in China. Therefore, the “kiln–house isomorphism” is generally adopted for the construction of pavilions in Shanxi. This study focuses on Xiaonanzhuang Village, Yuci District, Jinzhong City, Shanxi Province. Taking the Xiang-ming Pavilion, the core building of the village, as an example, we analyze the architectural characteristics of the “kiln–house isomorphism” in the pavilion in this area, describe the general construction rules of the region, and conduct a deep investigation of the five “cultural isomerism” factors of the pavilions in the region, namely, geomancy, etiquette and music, beliefs, clans, and cultivation and study. The results of this research will enrich the regional knowledge of such pavilions and add new objects for the protection of local architectural heritage, providing a theoretical basis for the contemporary adaptive reuse of pavilions in the Yuci area from a cultural perspective.

Is Zagreb Green Enough? Influence of Urban Green Spaces on Mitigation of Urban Heat Island: A Satellite-Based Study

The urban heat island phenomenon is a climatic condition in which urbanized areas exhibit higher temperature values than their natural surroundings. This occurs due to an unbalanced energy budget caused by the extensive use of synthetic materials. In such a scenario, urban green areas act as stressors to mitigate the intensity of the urban heat island and improve urban well-being. This study analyzes the spatial-temporal characteristics of the urban heat island in Zagreb, Croatia, aiming to examine the role of different types of green infrastructure in mitigating elevated temperature values and facilitating the definition of greener planning strategies. To achieve this, a multitemporal remote sensing- and NDVI-based analysis was conducted for the time series 1984–2014. An urban heat island intensity map was obtained for the selected 30-year period, along with thermal graphs registering land surface temperature values among different city districts. The results reveal significant heterogeneity, displaying variable behavior dependent on the city district. The role of Zagreb’s urban green areas in urban heat island mitigation is evident but largely dependent on urban morphology, construction types, and periods. Urban forests and urban parks play the most significant role in temperature reduction, followed by residential building neighborhoods and extensive neighborhoods consisting of familiar houses with gardens. Continuously built areas, such as the city center and industrial zones, are less prone to registering lower intensity values. Additionally, multitemporal intensity variations based on land use changes are registered in several districts.

Study of the acoustic features and exposures of some typical construction noise sources in India

Occupational noise research and occupational noise standards to date are limited to continuous, non-fluctuating broadband noise and uniform exposure. However, in many occupational environments, such as the construction sites, the workers may be exposed to continuous or intermittent noise of varied spectral and temporal patterns, and their exposure may not be continuous or uniform. These differences in sound signals and sound exposures may have different effect on humans. This paper studies the sound signals of various sources in construction sites of the institute campus through in-situ measurements. The key acoustic features and the spectral content of the sound signals are analyzed. The findings show that construction workers in India are exposed to construction noise with widely varying spectral content. A modified permissible upper limit of construction noise is developed for the presented case study and it is found that five out of eight studied construction sources violate the permissible limit and pose a noise hazard to the construction workers. The study suggests the need for updating occupational noise guidelines based on the noise types and exposure types; and imposing stricter measures for protecting the workers against the construction noise.

Seismic Vulnerability Indices of Facades of Colonial Houses in the Historic Center of Morelia, México

Evaluating the seismic vulnerability of facades of historic masonry buildings is essential not only for their significant historical and heritage value, but also to evaluate the safety of this type of construction. This work applies a simplified methodology to assess the seismic vulnerability of the facade of masonry buildings in the historic center of Morelia, Michoacán, México. The historic center of Morelia was declared a World Cultural Heritage Site by UNESCO in 1991. On the facades, there is ornamentation with sculptural and vegetal decorative elements. The methodology involved conducting visual inspections to identify the location, type of structure, construction materials, doors, windows, balconies, cornices, ironwork, pediments, niches, and sculptures, among other characteristic elements of colonial architecture. The seismic demands were determined specifically for the city’s historic center based on a recent seismic hazard assessment of Morelia. Based on the methodology and the compiled database, characterized vulnerability indices were defined for the different damage scenarios that buildings may present. Results indicate that earthquakes with intensities greater than VIII on the Modified Mercalli scale risk collapsing heritage masonry buildings’ facades.

Insights into Advances and Applications of Biomaterials for Nerve Tissue Injuries and Neurodegenerative Disorders.

The incidence of nerve tissue injuries, such as peripheral nerve injury, spinal cord injury, traumatic brain injury, and various neurodegenerative diseases (NDs), is continuously increasing because of stress, physical and chemical trauma, and the aging population worldwide. Restoration of the damaged nervous system is challenging because of its structural and functional complexity and limited regenerative ability. Additionally, there is no cure available for NDs except for medications that provide symptomatic relief. Stem cells offer an alternative approach for promoting damage repair, but their efficacy is limited by a compromised survival rate and neurogenesis process. To address these challenges, neural tissue engineering has emerged as a promising strategy in which stem cells are seeded or encapsulated within a suitable biomaterial construct, increasing cell survival and neurogenesis. Numerous biomaterials are utilized to create different types of constructs for this purpose. Researchers are trying to develop ideal scaffolds that combine biomaterials, cells, and molecules that exactly mimic the biological and mechanical properties of the tissue to achieve functional recovery associated with neurological dysfunction. This review focuses on exploring the development and applications of different biomaterials for their potential use in the diagnosis, therapy, nerve tissue regeneration, and treatment of neurological disorders.

Infrastructure distribution in cities and the improvement of the well-being of citizens in Japan: evidence from the quantile regression

ABSTRACT Urban construction under the aging society needs to provide efficient services for residents. We investigated the heterogenous relationship between various types of municipality-level critical infrastructure and park construction and the subjective well-being of citizens based on quantile regression using original survey data and the Japanese government statistics bureau of 2015-2017. Positive relationships were found in the low-and middle-level life satisfaction regions owing to the construction of museums or libraries, government branches, government services, health centers, police stations, fire stations, schools, hospitals, post offices, disabled and senior centers, and parks. Moreover, citizens were more likely to feel safe if the living community had comprehensive government-related institutions, including government offices, police stations, fire stations, schools, and post offices, among others. Our results indicated that the number of favorable infrastructures should be increased in areas with low levels of life satisfaction and less-safe communities to improve the citizens’ overall well-being.

خصائِص التّراكيب في شِعر الأضياف في حَماسِة أبي تمام: دِراسة تَحليليّة بلاغيّة

This study aims to apply rhetorical and semantic rules to the "Chapter of Guests" in Abu Tammam's Ḥamāsah. It focuses on rhetorical structures with different patterns through the relationship between the predicate and the subject, whether in literal or metaphorical predication, as well as the types of information, affirmations, imperative and non-imperative constructions, and the characteristics of sentence components, including: (restriction, omission, and mention). The study discusses the rhetorical purposes carried by these structures. Grammarians have delved deep into poetry and its meanings, as poetry is an aesthetic phenomenon that stems from language, reflecting human genius. Scholars and grammarians have explored the vocabulary and suggestive meanings of poetry to uncover its essence. This study also addresses some grammatical rules, given the high quality of Abu Tammam's choices in wisdom and eloquence. Abu Tammam was a prominent figure, engaging linguists with his poetry through various studies and research.