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The existing roofing system in tropical climates is not adapting to the worsening climate, along with the demand for sustainable building design; this study introduced a pioneering cool roof system to reform the traditional roofing system. The pioneering cool roof system is composed of white reflective coating, hollow foamed concrete roof (HFCR) tile, and a sustainable active reflective insulation (RI) system. Despite the complex integrated roof technologies, the study adopted 3D CFD numerical simulation for an in-depth and frontier thermal distribution analysis and fluid flow presentation. The outcomes of the numerical model were compared with field measurements for validation purposes, which resulted in just a 3.31% error. The internal attic was 35.64 °C despite the roof exterior achieving 54.59 °C after receiving an average 680 W/m2 solar radiation source. After the heat flux was hugely terminated by the HFCR tile and sustainable active RI system, the heat flux magnitude attained in the internal attic was 1.0822 W/m2, and the active RI system removed 96.29% of heat flux excellently. Meanwhile, the proposed roofing design's energy-saving performance was 27.5%.

The penetration of increasing solar gain towards the building deteriorates the building's thermal quality and raises cooling demand. In particular, the roof receives the most solar gain. The roof system reformation is urged to improve the roof system's heat capacity and conserve building energy. This paper introduced a novel cool roofing system to replace the traditional roof system. The proposed novel cool roofing applications merged: (i) lightweight foam concrete, (ii) hollow concrete slab, (iii) white cooling paint and (iv) active reflective insulation system powered by solar energy. The discovery of the proposed system was evaluated with experimental chambers exposed to the outdoor environment. Under intense sunlight, the internal roof surface was 30.6 % cooler (50.5 °C to 35.0 °C). The mean attic temperature achieved was 33.9 °C under a field where the daily maximum recorded surrounding temperature is 43.0 °C. In contrast with a bare roof at 41.9 °C, the proposed design demonstrated a 19.2 % lower solar gain, achieving a sub-ambient structure. Besides that, the cooling demand simulation generated similar cooling demand savings (20 %). Significantly, this comprehensive cool roofing system exhibited a considerable and constructive outcome in cooling the buildings by achieving sustainable development to create a better and more environmental future for all.

Grouping is a common phenomenon that occurs everywhere. The leader-follower relationship inside groups has often been qualitatively characterized in previous models using simple heuristics. However, a general method is lacking to quantitatively explain leadership in an evacuating group. To understand the evolution of single-group dynamics throughout an evacuation, we developed an extended social force model integrated with a group force. A series of single-group evacuations from a room were simulated. An information-theoretic method, transfer entropy (TE), was applied to detect predefined and undeclared leadership among evacuees. The results showed that the predefined leader was correctly detected by TE, suggesting its capability in measuring leadership based on time series of evacuees’ movement information (e.g., velocity and acceleration). When evacuees were grouped together, TE was higher than when they were alone. Leaders presented a monotonically increasing cumulative influence curve over the investigated period, whereas followers showed a diminishing tendency. We found that leadership emergence correlated with evacuees’ spatial positions. The individual located in the foremost part of the group was most likely to become a leader of those in the rear, which concurred with the experimental observations. We observed how a large group split into smaller ones with undeclared leadership during evacuation. These observations were quantitatively verified by TE results. This study provides novel insights into quantifying leadership and understanding single-group dynamics during evacuations.

Exit choice is essential for pedestrian safety and evacuation efficiency during the context of an emergency. Cumulative prospect theory is a widespread realistic decision-making theory that can transform choice outcomes and probabilities into subjective terms and integrate them as a parameter of cumulative prospect value (CPV), which determines the decision. The main contribution of this paper is the use of the CPV to predict exit choice. Furthermore, the different decision-making rules including Max, exponential(Expo), and Ratio (i.e., the three variable choice functions) were summarized and examined. This study used a confusion matrix to compare the predicted results with experimental data. Consequently, the parameters of Accuracy and F1-score showed that the predictions from Max and Expo were significantly more realistic while the results from Ratio were much more robust.

Using lightweight fire-rated board (LFRB) presents cost-effective opportunities for various passive fire protection measures. The aim of the project is to develop an LFRB with enhanced fire resistance, acoustic properties, and mechanical properties. These properties were determined using a Bunsen burner, furnace, energy-dispersive X-ray, impedance tube instrument, and Instron universal testing machine. To fabricate the LFRBs, vermiculite and perlite were blended with flame-retardant binders, and four types of LFRBs were produced. A fire test was conducted to compare the fire-resistance performance of the LFRBs with a commercially available flame-retardant board. The B2 prototype showed exceptional fire-resistant properties, with a temperature reduction of up to 73.0 °C, as compared to the commercially available fire-rated magnesium board. Incorporating nano chicken eggshell into the specially formulated flame-retardant binder preserved the LFRBs’ structural integrity, enabling them to withstand fire for up to 120 min with an equilibrium temperature of 92.6 °C. This approach also provided an absorption coefficient of α = 2.0, a high flexural strength of 3.54 MPa, and effective flame-retardancy properties with a low oxygen/carbon ratio of 2.60. These results make the LFRBs valuable for passive fire protection applications in the construction and building materials industry.

In a high-rise building fire, vertical shafts are the main paths for hot smoke to spread to multiple floors, posing a significant fire hazard. In this work, the large eddy simulation (LES) was applied to simulate smoke dynamics in a full-scale stairwell and study the influence of ambient pressure and heat release rate (HRR). The results have shown that the air mass flow rate into the stairwell decreases as ambient pressure drops on account of the lower air velocity and density and increases with HRR because of the stronger stack effect and increased smoke production. An equation incorporating ambient pressure and HRR is proposed for predicting the air mass flow rate. The temperature of hot smoke near the fire source increases with the reduced ambient pressure, while on the floors away from the fire source, the temperature decreases due to the higher temperature attenuation at a lower pressure. In addition, an empirical model is put forward for predicting the rising time of the smoke plume considering ambient pressure. The results could increase the basic understanding of smoke movement mechanisms and contribute to engineering applications of smoke control in high-rise building fires under reduced ambient pressure conditions.

The model-based predictive control (MPC) is considered to be an effective tool for optimal control of building heating, ventilation, and air-conditioning (HVAC) systems. MPC need to update the operating set points of the local control loops that have a significant influence on the energy performance of the system. Performance of MPC relies on the accuracy of the system performance model. There are two commonly used modeling approach – conventional or analytical approach that is the way of process modeling for some time, but it tends to increase the online computational load as it requires a full mathematical description of the real system. Furthermore, such techniques rely on different simplifying assumptions that limit the accuracy of the performance model. A second commonly used technique is the data-driven approach. The neural network (NN) is the most potent data-driven approach. NN can accurately model complex nonlinear systems without even knowing the structure of the system and it also addresses the problem of the online computational load since the computational load moves to the offline training step. In order to set up neural network model-based predictive control (NNMPC), it is important to build a reliable energy model of HVAC system that can be used to perform multi-step-ahead prediction of system energy performance. In this paper, the energy modeling of the chiller plant is conducted. Data for the training of chiller plant energy model is generated from HVAC testbed build in TRNSYS simulation environment. The nonlinear-autoregressive neural network with exogenous input (NARX) is used to model the energy performance of the chiller plant. The NARX is a powerful method for forecasting of time series data and dynamic control problems. NARX model is first trained in the open-loop form with the actual output instead of feedback, using back-propagation with the Levenberg-Marquardt method; this model can be used to perform only one-step-ahead prediction. Open-loop NARX model is transformed into a closed-loop form, by connecting the internal feedback, i.e. actual output is replaced by predicted output, to perform multi-step-ahead prediction (for predictive control). Comparative analysis of developed NARX-based chiller model is carried out with respect to process data from testbed, which demonstrated the good accuracy of the NARX-based chiller model.

The multiple beneficial effects of Al2O3 nanoparticle addition to cast magnesium based systems (followed by extrusion) were investigated, constituting either: (a) enhanced strength; or (b) simultaneously enhanced strength and ductility of the corresponding magnesium alloys. AZ31 and ZK60A nanocomposites containing Al2O3 nanoparticle reinforcement were each fabricated using solidification processing followed by hot extrusion. Compared to monolithic AZ31 (tension levels), the corresponding nanocomposite exhibited higher yield strength (0.2% tensile yield strength (TYS)), ultimate strength (UTS), failure strain and work of fracture (WOF) (+19%, +21%, +113% and +162%, respectively). Compared to monolithic AZ31 (compression levels), the corresponding nanocomposite exhibited higher yield strength (0.2% compressive yield strength (CYS)) and ultimate strength (UCS), lower failure strain and higher WOF (+5%, +5%, −4% and +11%, respectively). Compared to monolithic ZK60A (tension levels), the corresponding nanocomposite exhibited lower 0.2% TYS and higher UTS, failure strain and WOF (−4%, +13%, +170% and +200%, respectively). Compared to monolithic ZK60A (compression levels), the corresponding nanocomposite exhibited lower 0.2% CYS and higher UCS, failure strain and WOF (−10%, +7%, +15% and +26%, respectively). The capability of Al2O3 nanoparticles to enhance the properties of cast magnesium alloys in a way never seen before with micron length scale reinforcements is clearly demonstrated.

A hybrid magnesium alloy nanocomposite containing AlN nanoparticle reinforcement was fabricated using solidification processing followed by hot extrusion. The nanocomposite exhibited similar grain size to the monolithic hybrid alloy, reasonable AlN and intermetallic nanoparticle distribution, nondominant (0 0 0 2) texture in the longitudinal direction, and 17% higher hardness than the monolithic hybrid alloy. Compared to the monolithic hybrid alloy, the nanocomposite exhibited higher tensile yield strength (0.2% TYS) and ultimate tensile strength (UTS) without significant compromise in failure strain and energy absorbed until fracture (EA) (+5%, +5%, −14% and −10%, resp.). Compared to the monolithic hybrid alloy, the nanocomposite exhibited unchanged compressive yield strength (0.2% CYS) and higher ultimate compressive strength (UCS), failure strain, and EA (+1%, +6%, +24%, and +6%, resp.). The overall effects of AlN nanoparticle addition on the tensile and compressive properties of the hybrid magnesium alloy is investigated in this paper.

A hybrid magnesium alloy nanocomposite containing TiC nanoparticle reinforcement was fabricated using solidification processing followed by hot extrusion. The nanocomposite exhibited similar grain size to the monolithic hybrid alloy, reasonable TiC nanoparticle distribution, nondominant (0 0 0 2) texture in the longitudinal direction, and 16% higher hardness than the monolithic hybrid alloy. Compared to the monolithic hybrid alloy, the nanocomposite simultaneously exhibited higher tensile yield strength (0.2% TYS), ultimate tensile strength (UTS), failure strain, and work of fracture (WOF) (+14%, +7%, +81%, and +92%, resp.). Compared to the monolithic hybrid alloy, the nanocomposite exhibited lower compressive yield strength (0.2% CYS) and higher ultimate compressive strength (UCS), failure strain, and WOF (–11%, +7%, +4%, and +15%, resp.). The advantageous effects of TiC nanoparticle addition on the enhancement of tensile and compressive properties of the hybrid magnesium alloy are investigated in this paper.

The contribution of teacher knowledge to learning outcomes at the beginning stages of literacy acquisition is of growing concern because the ability to provide quality instruction is central to successful literacy acquisition, particularly for pupils with dyslexia. To date, the majority of research has focused on teachers of English as a first language. Yet, English is the most widely taught foreign language today. The present study extends the exploration of teacher knowledge by probing two heretofore unexamined groups of teachers who are responsible for teaching beginning stages of literacy in English as a foreign language: regular class teachers who are non-native English-speaking (N = 96) and native English-speaking teachers (N = 24) working in the kindergarten setting in Hong Kong. As these two teacher groups serve as gatekeepers of beginning English as a foreign language literacy for kindergarten children in Hong Kong, it is crucial to gather information about the depth and quality of their teacher knowledge. This information can be instrumental to improving the quality of beginning literacy instruction in English and assisting early identification of dyslexia. Both groups completed the basic language constructs survey (Binks-Cantrell, Joshi, & Washburn, "Annals of Dyslexia," 62, 153-171, 2012a). Results showed while native English teachers performed significantly better than non-native English teachers, total percentage correct scores were below 50%, except for phonological awareness tasks. All teachers scored higher in items requiring syllable as opposed to phoneme manipulation. Only teacher type predicted teachers' performance on the survey. The need for quality instruction, particularly for children at-risk for dyslexia or those struggling at the beginning stages of literacy acquisition, is addressed.

The present longitudinal study investigated the role of spelling as a bridge between various reading-related predictors and English word reading in Chinese children learning English as a Second Language (ESL). One hundred and forty-one 5-year-old kindergarten children from Hong Kong, whose first language (L1) was Cantonese and second language (L2) was English, were administered tests of phonological awareness, letter knowledge, English vocabulary, spelling and English word reading at three time points (T1, T2 and T3) at 3-month intervals over a 6-month period. Nonverbal IQ was included as a control variable. The results showed that phonological awareness, letter knowledge and English vocabulary at T1 all predicted English word reading (T3) through spelling (T2). Further mediation analyses showed that, for phonological awareness and English vocabulary, full mediation effects were found. For letter knowledge, a partial mediation effect was observed. These results suggest that, in Chinese ESL kindergarteners, reading-related predictors foster word reading via spelling, a process that intersects phonology, orthography and semantics. Practical implications of these findings were also discussed.

The study seeks to understand the relation between preschool children's mode of participation and negotiation strategies during play and their theory of mind (ToM) development in the Hong Kong context. Forty-two 5-year-old children were recruited. Their emotional and cognitive ToMs were assessed along with expressive language ability. Children's play was observed twice in naturalistic and laboratory settings. Parents completed a questionnaire on their child's emotional and cognitive ToM development, including demographic information and social economic status indexes. The results showed that 5-year-old Hong Kong children mostly engaged in associative and cooperative play and employed two-way, reciprocal strategies in their play. Parent report of emotional ToM predicted children's play strategy in both naturalistic and laboratory settings. Child measure of cognitive ToM predicted their play strategy in the laboratory setting. The study advocates more play time in kindergarten in order to foster an empathetic generation.

This paper highlights the crucial role of phonological instruction in early second language English learning. Although older learners can acquire grammar and vocabulary efficiently, younger learners appear to have a greater facility with the learning of sounds. Thus, it makes good sense to focus on articulatory skills for these early learners. By comparing the developmental norms in phonology between an L1 (Cantonese in this study) and an L2, detailed predictions can be provided to guide the process of early phonological instruction. It is important that the teaching of articulation should not be reduced to non-engaging lessons that can be characterised as "drill and kill". Instead, a framework for improving the articulation of children learning English as a second language is proposed. What is unique about this proposal is that it represents the first attempt in Hong Kong to specify and integrate research findings concerning developmental speech norms with existing teaching practice. (Contains 3 tables.)

We examined the relationship between the acoustic duration of syllables and the silent pauses that follow them in Cantonese. The results showed that at major syntactic junctures, acoustic plus silent pause durations were quite similar for a number of different syllable types whose acoustic durations differed substantially. In addition, it appeared that CV: syllables, which had the longest acoustic duration of all syllable types that were examined, were also the least likely to have silent pauses after them. These results suggest that cross-language differences between the probability that silent pauses are used at major syntactic junctures might potentially be explained by the accuracy at which timing slots can be assigned for syllables, rather than more complex explanations that have been proposed. (Contains 2 tables, 5 figures and 2 footnotes.)