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Translation accuracy is one of the most critical factors for protein synthesis. It is regulated by the ribosome and its dynamic behavior, along with translation factors that direct ribosome rearrangements to make translation a uniform process. Earlier structural studies of the ribosome complex with arrested translation factors laid the foundation for an understanding of ribosome dynamics and the translation process as such. Recent technological advances in time-resolved and ensemble cryo-EM have made it possible to study translation in real time at high resolution. These methods provided a detailed view of translation in bacteria for all three phases: initiation, elongation, and termination. In this review, we focus on translation factors (in some cases GTP activation) and their ability to monitor and respond to ribosome organization to enable efficient and accurate translation.This article is categorized under:Translation > Ribosome Structure/FunctionTranslation > Mechanisms

IntroductionCorona Virus-induced disease – 2019 (COVID-19) pandemic stimulates research works to find a solution to this crisis from starting 2020 year up to now. With ending of the 2021 year, various advances in pharmacotherapy against COVID-19 have emerged.Regarding antiviral therapy, Casirivimab and imdevimab antibody combination is a type of new immunotherapy against COVID-19. Standard antiviral therapy against COVID-19 includes Remdesivir and Favipravir.Aim of StudyTo compare the efficacy and safety of antibodies cocktail (casirivimab and imdevimab), Remdesivir, and Favipravir in the COVID-19 patientsPatients and Population265 hospitalized COVID-19 patients were used to represent the COVID-19 population and were assigned into three groups in a ratio of (1:2:2) respectively, Group (A) received REGN3048-3051(Antibodies cocktail (casirivimab and imdevimab), group (B) received remdesivir, and group (C) received favipravir.MethodsThe study design is a single-blind non-Randomized Controlled Trial (non-RCT). The drugs of the study are owned by Mansoura University Hospital (MUH) and prescribed by chest diseases lectures of the faculty of medicine-Mansoura University. The duration of the study is about 6 months after ethical approval.Results and discussionCasirivimab and imdevimab achieve less 28-day mortality rate, less mortality at hospital discharge, more negative swab cases, less need for O2 therapy and IMV, less duration of this need, less hospital and ICU stay, less case progression as presented by lower World Health Organization (WHO) scale and better multi-organ functions as presented by lower Sequential Organ Function Assessment (SOFA) score than Remdesivir and Favipravir.ConclusionFrom all of these results, it is concluded that Group A (Casirivimab & imdevimab) has more favorable clinical outcomes than B (remdesivir) & C (favipravir) intervention groups.Clinical Trial Registration:NCT05502081, 16/08/2022,Clinicaltrials.gov, retrospectively registered

Background: COVID-19 is an abnormal host response to the SARS-CoV-2 infection, which is associated with endothelial dysfunction and multi-organ failure. Atorvastatin has been proposed to reduce COVID-19 severity and mortality. Methods: This randomized double-blind trial included 220 COVID-19 patients admitted to Mansoura University's isolation hospital in Egypt. One hundred and ten cases were given 40 mg of atorvastatin once daily for 28 days (group A), while 110 received a placebo (group B). All patients received treatment as per hospital protocol. The primary outcome is all-cause mortality at 28 days. We also tracked six-month mortality, time to clinical improvement, the risk of invasive mechanical ventilation, acute kidney injury, potential adverse events, and hospital and intensive care length of stay. Results: The 28-day all-cause mortality was 52/104 (50%) in group A vs. 54/103 (52.4%) in group B, odds ratio (OR) = 0.907 (0.526, 1.565), P = 0.727; adjusted OR = 0.773 (0.407, 1.47), P = 0.433. Six-month mortality occurred in 53/102 (52%) and 59/79 (60.8%) in group A vs. B, respectively, P = 0.208. Among hospital survivors in group A vs. group B, the median time to clinical improvement was 10 days (7–14) vs. 10 (7–15), P = 0.715; the duration of hospital stay was 10 days (7–14) vs. 10 (8–17), P = 0.378. Discontinuation was higher in group B (four vs. one), P = 0.369. Conclusions: In adults with severe or critical COVID-19, atorvastatin did not reduce the risk of 28-day or six-month mortality and did not improve other clinical outcomes. Trial registration: Clinical Trial Registry (NCT04952350) on July 1st, 2021. https://clinicaltrials.gov/ct2/show/NCT04952350

Introduction: Corona Virus induced disease – 2019 (COVID-19) disaster motivates scientific research to find a settling to this pandemic. With ending of 2021 year, various advances in immunotherapy against COVID-19 have emerged. Regarding antiviral therapy, Casirivimab and imdevimab antibody combination is a type of new immunotherapy against COVID-19. Other antiviral therapy against COVID-19 includes Remdesivir and Favipravir. Aim of Study: To compare the efficacy and safety of casirivimab and imdevimab, Remdesivir and Favipravir as antiviral agents in hospitalized COVID19 patients. Patients and Population: 265 COVID-19 Polymerase Chain Reaction (PCR) positive patients are included in this study and will be assigned into 3 groups in a ratio of (1:2:2): 1- Group A: REGN3048-3051 2-group B: Remdesivir 3-group C: Favipravir Methods: Study design is single blind non-Randomized Controlled Trial (non-RCT). The duration of study is about 6 months after ethical approval. Results and discussion: Casirivimab and imedivimab achieves less 28-day mortality rate, less mortality at hospital discharge, more negative swab cases than Remdesivir and Favipravir. Conclusion: the results show that Group A (Casirivimab & imedivimab) achieves more favorable clinical outcomes than B (remdesivir) & C (favipravir) groups.

Background: Colorectal cancer is one of the most frequent causes of cancer-related death worldwide. An accurate preop-erative rectal cancer staging is crucial to the correct manage-ment of the disease. Despite great controversy around this issue, pelvic magnetic resonance is said to be the standard modality. Aim of Study: The aim of this study is to assess the role of MRI in detection and local staging of rectal cancer. Patients and Methods: 30 patients with rectal carcinoma were included with MRI and histopathological assessment of cancer staging to evaluate MRI accuracy. All patients received pre-operative neoadjuvant chemotherapy. Results: T3 staging with MRI, calculation of sensitivity, specificity, negative and positive predictive value were 73.3%, 40%, 60% and 55% respectively. T4 staging with MRI, cal-culation of sensitivity, specificity, negative and positive predictive value were 100%, 77%, 100% and 40% respectively. Conclusion: MRI has a good sensitivity for tumor staging and nodal staging.

The Mo-dependent enzyme YiiM enzyme from Escherichia coli is a member of the sulfite oxidase family and shares many similarities with the well-studied human mitochondrial amidoxime reducing component (mARC). We have investigated YiiM catalysis using electrochemical and spectroscopic methods. EPR monitored redox potentiometry found the active site redox potentials to be Mo

This paper evaluates the effect of dynamic thermal conductivity (λ) change of expanded polystyrene insulation (EPS) on temperature change through a conventional wall assembly at varying positions of the insulation within the assembly in question. According to the findings, in the case of the application of the variable λ-value of the insulation, compared to that obtained when the constant λ-value for polystyrene (EPS) insulation is adopted in the same conditions, the temperature profile through the wall assembly during the daytime is greater. In the event of applying the constant and variable λ-values, the temperature shift on the inside is seen to decline as the location of the insulation material is positioned towards the surface of the inner wall. The highest level of time lag between position 1 to 2 is over 1.3 h and around 3.47 h between position 1 and 3, and as the density level of the insulation materials rises, it leads to better transient thermal performance due to a lower temperature rise on the inside wall surface. These results suggest that considering betterment in the insulation's thermal conductivity would provide the most performant wall configuration by placing the material in the middle of the wall assembly, taking into account the change in the thermal conductivity of the insulation.

This work presents the combined microwave assisted synthesis, spectroscopic analyses, cytotoxic effects, and molecular docking studies of the chromene fused ring systems with various substituents of the terminal halogenated phenyl ring derivatives of 6-methoxy-4H-benzo [h]chromene (4a-m). The structures of the synthesized compounds were established on the basis of their spectral data, IR, 1H NMR, 13C NMR, 13C NMR-DEPT, and MS data. The target compounds were evaluated for their antitumor activities against three cancer cell lines: MCF-7, HCT-116, and HepG-2, in comparison to Vinblastine and Colchicine as reference drugs with the usage of a MTT colorimetric assay. The most active compounds were subjected to further mechanistic analysis through the assay of the c-Src Kinase inhibition activity. The SAR studies reported that the substitution at the 4-position of the 2-amino-4H-benzo [h]chromene nucleus with specific halogen atoms and lipophilic characters increased the ability of the molecule against the different cell lines. The Molecular Operating Environment (MOE) was used to evaluate the interactions between the ligand and the c-Src Kinase enzyme. Compound 4m, having the 3,5-dibromo-2-methoxyphenyl group attached to the 4H-benzo [h]chromene moiety at the 4-postion, exhibited a promising interaction with the c-Src Kinase, which leads to a strong inhibition of this enzyme.

In this paper, novel geopolymer-coated expanded clay-phase change material (GP- L -PCM) macrocapsules added to geopolymer concrete (GPC) with volume ratios of 25%, 50%, and 75% for the production of GP- L -PCM slabs are described. The same amounts of lightweight expanded clay aggregate (LECA) were used to develop LECA slabs. The thermal and structural performances of LECA and GP- L -PCM slabs were compared with a reference GPC slab. It was observed that LECA and GP- L -PCM slabs exhibit lower heat transmission, represented by lower maximum surface temperatures (a decrease of 5.6 °C and 8.0 °C on the back surface) than that of GPC slab. Accordingly, the LECA and GP- L -PCM slabs exhibit U-values of 1.6 and 0.9 W/m2K, respectively, with 75% addition of LECA and GP- L -PCM capsules compared to 2 W/m2K for GPC. Substantial decrease in compressive strength was observed in the LECA and GP- L -PCM slabs as compared to GPC for all tested samples.

Due to the hot climate of the United Arab Emirates (UAE), where the external ambient temperature may reach 50°C in the summer season, almost 75% of the total energy is consumed in air-conditioning (AC). A significant improvement in the AC systems performance during hot summer time aligned with energy conservation could be achieved by pre-cooling of the air entering the condensers. Inclusion of Phase Change Material (PCM) as thermal energy storage (TES) have been widely used as one of the environmentally friendly energy saving materials due to its high energy density. The absorption/releasing of heat by PCM during its phase change, provides a latent heating/cooling for the surrounding. Numerous systems have implemented PCM based-TES for cooling purposes, such as thermally activated building systems (TABS), suspended ceilings, external facades or in the ventilation system. This study examines PCM based air pre-cooling concept and evaluates its performance in extremely hot climate of UAE. The drop in the outlet air temperature of the duct system quantifies the cooling effect. A paraffin based PCM with melting range of 30–33°C integrated in containers placed in the test chamber mimic the air conditioning duct system, and its cooling effect is monitored. A Conjugate heat transfer model employing enthalpy-based formulation is developed to predict the optimized PCM container size and optimum airflow rate validated with experimental data. Single and series columns of PCM containers subjected to different levels of supplied air velocity at range of 1 m/s - 4m/s are evaluated. Employing series of PCM enclosures at low air velocity of 1m/s enhanced the pre-cooling performance and reduced the outlet air temperature to 35°C yielding a temperature drop up to 11°C.

The current article evaluates a method of cooling low concentration photovoltaic (CPV) through the solid-liquid phase change material (PCM) to mitigate temperature-based power losses and utilize the recovered heat. The heat stored in the melted PCM is exchanged with domestic supply water, thus developing a novel CPV-PCM thermal (CPV-PCM/T) system. The CPV-PCM/T system is evaluated outdoors in the extreme hot weather conditions of Al Ain, United Arab Emirates (UAE) for the three consecutive days. The energy performance of CPV-PCM/T system is compared to the ordinary flat plate collector (FPC) and the experiments run simultaneously at the same site. Although the CPV-PCM/T produces lesser net energy (1527 kWh/m2-day) compared to FPC (1803 kWh/m2-day) yet the cost of production is 28% lower than the FPC.

Background One of the major abiotic stressors that have a serious effect on plant growth and productivity worldwide is the salinity of soil or irrigation water. The effect of foliar application of magnetite nanoparticles (size = 22.05 nm) at different concentrations (0, 0.25, 0.5, and 1.0 ppm) was investigated to improve salinity tolerance in two wheat cultivars, namely, Misr1 (Tolerant) and Gimmeza11 (Sensitive). Moreover, toxicological investigations of magnetite oxide nanoparticle in Wistar albino rats were estimated. Results The magnetite nanoparticles positively affected growth, chlorophyll, and enzymatic antioxidants such as superoxide dismutase (SOD), stimulating reduced glutathione and improving the aggregation of several polypeptide chains that may be linked to the tolerance of saline stress. In contrast, magnetite nanoparticles reduced malondialdehyde (MDA). Inverse sequence-tagged repeat (ISTR) assay of DNA molecular marker showed the change in band numbers with the highest polymorphic bands with 90% polymorphism at primer F3, B5 and 20 positive bands in Gimmeza11 with 0.5 ppm magnetite nanoparticles. In the median lethal dose (LD50 ) study, no rats died after the oral administration of magnetite nanoparticle at different doses. Therefore, the iron oxide nanoparticle was nontoxic when administered orally by gavage. Conclusion Magnetite nanoparticles partially helped to alleviate the effects of salt stress by activating growth, chlorophyll content, SOD, glutathione, and soluble proteins in two wheat cultivars (Misr1 and Gimmeza11) and decreasing MDA content. © 2021 Society of Chemical Industry.

Wear debris provides important information about the machine condition that can be used to prevent the loss of expensive machinery. This information is crucial as it portrays the condition of the machines and can be used to predict early failure of the machinery that can prevent a major loss to the industry. Wear debris or particles produced in different parts of machine vary in shape, size, color, and texture. These characteristic features can be utilized to identify the type of wear debris. Human experts are extremely efficient in recognizing such objects; however, wear judgments are occasionally based on their specific perceptions. The goal is to look beyond the personal opinions and bring consistency in judging and recognizing wear particles. Keeping in view the above findings, this study focuses on the identification of wear particles by using shape-based features only. Different shape features, which include the Histogram of Oriented Gradients (HOG), Rotation Scale Translation (RST) invariant features, solidity, aspect ratio, circularity, and Euler number, are extracted and used to train three classification models of Support Vector Machine (SVM), k-Nearest Neighbors (kNN), and discriminant analysis (DA) classifier. The performance of the classifiers are compared with each another and classification of debris based on shape features is analyzed.

The endogenous yeast 2-μm plasmid while innocuous to the host, needs to be properly regulated to avoid a toxic increase in copy number. The plasmid copy number control system is under the control of the plasmid encoded recombinase, Flp1. In case of a drop in 2-μm plasmid levels due to rare plasmid mis-segregation events, the Flp1 recombinase together with the cell’s homologous recombination machinery, produce multiple copies of the 2-μm plasmid that are spooled during DNA replication. The 2-μm plasmid copy number is tightly regulated by controlled expression of Flp1 as well as its ubiquitin and SUMO modification. Here, we identify a novel regulator of the 2-μm plasmid, the ATPase, ubiquitin ligase, Irc20. Irc20 was initially identified as a homologous recombination regulator, and here we uncover a new role for Irc20 in maintaining the 2-μm plasmid copy number and segregation through regulating Flp1 protein levels in the cell.

Memristor, the two-terminal memory-resistance device discovered by Chua in 1971, is a promising solution for future processing problems. Its CMOS integration compatibility and large resistance in small size, makes it very successful candidate for large-scale systems like Neural Networks. In last decade, memristors were used in many Neuromorphic Synapses for its advantage of combining processing (dot-product) and memory in same device. There are different materials that can be used to fabricate memristors. In this paper, a comparison between spintronic and TiO2-resistive memristor in two-transistors-one memristor synapse, is introduced. The work was done on Cadence Virtuoso with using Verilog-A for memristor modeling. The comparison reveals that the synaptic implementation with a spintronic memristor is more efficient when high speed is needed. However, the resistive memristor is more adequate due to its lower power dissipation.

This paper examines the change of the temperature through a typical wall assembly comprising a polystyrene insulation material (EPS) with constant and variable thermal conductivity (λ). Four levels of the insulation density, namely, low density (LD), high density (HD), super high density (SHD), and ultra-high density (UHD) impeded at three different locations within the wall have been considered in this study. During the day, the evolution of temperatures through the wall section was observed on inner wall surface when EPS is located at different positions of the wall section. Thereafter, the thermal performance across the wall section incorporating insulation layers at different positions applying variable λ-value was compared to a non-variable thermal conductivity case by quantifying the net heat reduction due to the λ-relationship with time. As a result obtained, the change of the temperature through the wall with variable λ is higher compared to the case of constant λ. The temperature change on the inner wall surface with constant and variable λ is shown to decrease as the position of the insulation material is located toward the inner wall surface. Therefore, locating the insulation material in the middle of the wall assembly will provide the best dynamic thermal performance.

Fun30 is an ATP dependent chromatin remodeler in budding yeast that is involved in cellular processes important for maintaining genomic stability such as gene silencing and DNA damage repair. Cells lacking Fun30 are moderately sensitive to the Topoisomerase inhibitor camptothecin and exhibit a delay in cell cycle progression in the presence of camptothecin. Here, we show that Fun30 is required to cope with torsional stress in the absence of Top1. Moreover, we show through genetic studies that Fun30 acts in a parallel pathway to Mus81 endonuclease but is epistatic to Tdp1 phosphodiesterase and Rad1 endonuclease in the repair of camptothecin induced DNA damage. More importantly, we show that DNA damage sensitivity of Fun30 deficient cells are enhanced in the absence of RNase H enzymes that remove RNA:DNA hybrids. We believe that, chromatin remodeling by Fun30 may be important in dealing with torsional stress and camptothecin induced DNA damage.

DNA double-strand breaks (DSBs) constitute one of the most cytotoxic forms of DNA damage and pose a significant threat to cell viability, survival, and homeostasis. DSBs have the potential to promote aneuploidy, cell death and potentially deleterious mutations that promote tumorigenesis. Homologous recombination (HR) is one of the main DSB repair pathways and while being essential for cell survival under genotoxic stress, it requires proper regulation to avoid chromosome rearrangements. Here, we characterize the Saccharomyces cerevisiae E3 ubiquitin ligase/putative helicase Irc20 as a regulator of HR. Using purified Irc20, we show that it can hydrolyze ATP in the presence and absence of DNA, but does not increase access to DNA within a nucleosome. In addition, we show that both the ATPase and ubiquitin ligase activities of Irc20 are required for suppressing the spontaneous formation of recombination foci. Finally, we demonstrate a role for Irc20 in promoting Rad51 chromatin association and the removal of Rad52 recombinase from chromatin, thus facilitating subsequent HR steps and directing recombination to more error-free modes.

Wear debris is produced in all machines containing moving parts. Wear debris or particles separate from these moving parts because of close contacts and friction and are contained in oil in an oil-wetted system. Analysis of wear debris provides important information about the condition of a machine. The produced particles come in different shapes, sizes, colors, and surface texture. This paper describes the morphological analysis of wear particles by using computer vision and image processing techniques. The aim is to classify these particles according to their shape attributes. Four particle shapes are classified by using Histogram of Oriented Gradients (HOG) and shape attributes including eccentricity, extent, major and minor axis length, equiv-diameter, and centroid distance. The shape classification can be used to identify origin of particle generation and thus predict wear failure modes in engines and other machinery. The objective of particle classification obviates reliance on visual inspection techniques and the need for specialists in the field.

Background/Aims: Breast cancer is the most common cancer in women worldwide, and within this cancer type, triple-negative breast cancers have the worst prognosis. The identification of new genes associated with triple-negative breast cancer progression is crucial for developing more specific anti-cancer targeted therapies, which could lead to a better management of these patients. In this context, we have recently demonstrated that SMARCAD1, a DEAD/H box-containing helicase, is involved in breast cancer cell migration, invasion, and metastasis. The aim of this study was to investigate the impact of the stable knockdown of SMARCAD1 on human breast cancer cell progression. Methods: Using two different designs of shRNA targeting SMARCAD1, we investigated the impact of the stable knockdown of SMARCAD1 on human breast cancer cell proliferation and colony growth in vitro and on tumour growth in chick embryo and nude mouse xenograft models in vivo using MDA-MB-231 (ER-/PR-/ HER2-) and T47D (ER+/PR+/-/HER2-) human breast cancer cell lines. Results: We found that SMARCAD1 knockdown resulted in a significant decrease in breast cancer cell proliferation and colony formation, leading to the significant inhibition of tumour growth in both the chick embryo and nude mouse xenograft models. This inhibition was due, at least in part, to a decrease in IKKβ expression. Conclusion: These results indicate that SMARCAD1 is involved in breast cancer progression and can be a promising target for breast cancer therapy.

This paper illustrates the impact of transient thermal conductivity of the insulation layer embedded in a typical residential building on cooling effect and energy performance. The test was performed applying expanded polystyrene (EPS), as an example of insulation material, in the extremely hot climate of UAE at different levels of densities, and three moisture content levels (10%, 20%, and 30%) compared to dry insulation material for Low density (LD) material. Thermal wall resistance was evaluated by applying a conjugate heat-transfer model based on enthalpy-based formulation. The thermal performance of the building incorporating expanded polystyrene with variable thermal conductivity was compared to non-variable thermal conductivity by quantifying the additional cooling demand and capacity due to the λ relationship with time using the e-quest as a building energy analysis tool. The results show that, when the λ value is modeled as a function of operating temperature, its effect on the temperature profile during daytime is significant. The LD expanded polystyrene insulation leads to the lowest heat resistance across the wall section. Applying different levels of moisture showed that 30% moisture content has the lowest heat resistance compared with 10% and 20%, resulting in the highest change of 6.5% and 8.9% in cooling demand and capacity, respectively. Keywords: Temperature profile, Building insulation materials, Operating temperature, Moisture content, Heat release, AC capacity

In our effort to develop novel and powerful agents with anti-proliferative activity, two new series of 1H-benzo[f]chromene derivatives, 4a–h and 6a–h, were synthesised using heterocyclocondensation methodologies under microwave irradiation condition. The structures of the target compounds were established on the basis of their spectral data, IR, 1H NMR, 13 C NMR, 13 C NMR-DEPT/APT, and MS data. The new compounds have been examined for their anti-proliferative activity against three cancer cell lines, MCF-7, HCT-116, and HepG-2. Vinblastine and Doxorubicin have been used as positive controls in the viability assay. The obtained results confirmed that most of the tested molecules revealed strong and selective cytotoxic activity against the three cancer cell lines. Moreover, these molecules exhibited weak cytotoxicity on the HFL-1 line, which suggested that they might be ideal anticancer candidates. The SAR study of the new benzochromene compounds verified that the substituents on the phenyl ring of 1H-benzo[f]chromene nucleus, accompanied with the presence of bromine atom or methoxy group at the 8-position, increases the ability of these molecules against the different cell lines. Due to their high anti-proliferative activity, compounds 4c and 6e were selected to be examined their proficiency to inhibit the invasiveness of the highly sensitive and invasive breast cancer cell line, MDA-MB-231. The anti-invasion behaviour of these molecules against the highly sensitive, non-oestrogen, and progesterone MDA-MB-231 cell line gave rise to their decreasing metastatic effect compared to the reference drug. Furthermore, this report explores the apoptotic mechanistic pathway of the cytotoxicity of the target compounds and reveals that most of these compounds enhance the Caspase 3/7 activity that could be considered as potential anticancer agents.

Although many advanced insulation materials have been recently developed, very few are eco-friendly and their production requires a substantial amount of energy and complex manufacturing processes. To address this issue, a bio-based thermal insulation material was developed using short- and long-grained puffed rice. A set of experiments was subsequently carried out to identify the best rice type and the optimal range for the most influential parameters (sample amount, temperature, and moisture level). Our findings revealed that short-grained rice exhibited greater puffing ability and was thus adopted in further material optimization experiments. These assessments indicated that the most optimal thermal conductivity of the insulation material and the highest puffing ratio was attained at 12–15% moisture, 260–270 °C temperature, and 15–18 g sample weight. The thermal properties, including thermal conductivity and fire reaction, and thermal performance of samples obtained using these parameters were similar to those of common insulation materials.

This paper investigated the impact of the changes of thermal conductivity of an expanded polystyrene insulation layer embedded in a typical residential building on the cooling effect at different temperatures and moisture contents. The simulation was performed using expanded polystyrene (EPS) in the extremely hot conditions of Al-Ain (United Arab Emirates, UAE) at different levels of density, denoted as low density LD (12 kg/m3), high density HD (20 kg/m3), ultra-high density UHD (30 kg/m3), and super-high density SHD (35 kg/m3), and three moisture content levels (10%, 20%, and 30%), compared to dry LD insulation material. The thermal performance of the building incorporating polystyrene with variable thermal conductivity (&lambda, value) was compared to one with a constant thermal conductivity by assessing the additional cooling demand and capacity due to the &lambda, relationship with time, using e-quest as a building energy analysis tool. The results showed that, when the &lambda, value was modeled as a function of operating temperature, its effect on the temperature profile during daytime was significant compared with the use of a constant &lambda, value. The monthly energy consumption for cooling required by the building was found to be higher in the case of variable thermal conductivity for the LD sample. The yearly average change in space cooling demand and cooling capacity when employing polystyrenes with constant and variable thermal conductivity increased with the increase of the moisture content. Indeed, the highest changes in cooling demand and capacity were 6.5% and 8.8% with 30% moisture content polystyrene.

In this work, the dynamic thermal effect of thermal conductivity, K-value, is investigated at different operating temperatures and moisture levels of polystyrene expanded insulation material (EPS) by using computational modelling of heat transport. In building energy analysis and assessment, the heat transfer through the building envelope usually considers a constant single K-value and neglects the effect of the moisture content within the insulation. In reality, the building envelope is subjected to the combined thermal and moisture gradients. Therefore, an accurate analysis requires a simultaneous calculation of both sensible and latent effects. The purpose of this paper is to analyze the dynamic thermal effect on the K-value of EPS by using the conduction finite difference (CondFD). The results of this research show a slight difference in the thermal conductivity value of EPS insulation at different operating temperatures for different densities of the material. However, a greater difference is observed at higher moisture contents compared with the dry sample when the K-value of the insulation is temperature dependent. Keywords: Thermal conductivity, Operating temperature, Moisture content, EPS insulation

Quantum dots (QDs) are semiconductor material with nano-crystal characterized by high absorption coefficient, retention time and re-emission in a desired direction with tunable spectrum. These characteristics render QDs favorable for concentrating solar radiation in the desired direction to form a quantum dot solar concentrators (QDSC). The extent of absorption and re-emission determines their effectiveness as concentrators. The QD effectiveness is influenced by type, shape, size, dot concentration and optical path length through the device. In order to optimize design of QDSC, the optimum doping concentration of QD in the QDSC devices is crucial. QDSC can be integrated to solar cells to improve PV integration and penetration to buildings. The QDSC embedded into glazing can help harvest solar energy by PV cells without affecting the occupants’ visual communication to outdoors thereby embodying energy producing transparent glazing. The aim of this paper is to review state of the art of QDSC integrated with solar cells applied in buildings. Several types of QDSC characterized by sizes, shapes and material will be discussed and analyzed based on their concentration effectiveness, visibility and environmental impact. The challenges faced by QDSC in terms of building integration i.e., cell overheating by concentrated radiation and the contemporary solutions will be discussed. The article helps building designers and system integrators assess the merits of the QDSC based solar cells in terms of system integration, energy production and visual comfort.

Concentrated photovoltaic (CPV) system is cooled through a phase change material (PCM) and associated improvement in energy performance is presented in this article. The CPV-PCM system is tested experimentally in extremely hot weather of Al Ain, United Arab Emirates (UAE), where the outside ambient temperature reached up to 55 °C under direct sun for three consecutive days. A commercial grade paraffin-based PCM with melting point in the range of (58–60) °C is integrated in the container attached to the back of the CPV panel to absorb the heat and cools the CPV while melting. The energy performance of the cooled CPV-PCM system is compared to that of non-cooled CPV to determine the increased energy outputs due to cooling produced by PCM. CPV and CPV-PCM yielded total energy efficiency of 30% and 60%, respectively, indicating the advantage of including PCM into CPV design. A 2-D conjugate heat transfer model employing enthalpy-based formulation is developed and validated with the experimental data. The validated numerical model is employed to identify optimum PCM types (paraffin, salt hydrate, and fatty acids), and optimize PCM container configurations for different heat intensities. The optimum PCM thickness of different tested PCMs: paraffin, fatty acid, and salt hydrate (SP) required for complete melting and solidification in the range of 55–60 °C was found to be 6, 9, 20 cm, respectively. The SP was found to be the optimum type of PCM employing less amount of material to achieve the same cooling performance, however, disadvantages of SP need to be considered.

Wear particle analysis is used for health monitoring of a machine to identify possible failure modes resulting from various machine components. One of the initial phases of analysis typically involves a microscopic examination of particles extracted from the lubrication system. Experts in the field (Tribologists) utilize this important information from these examinations to monitor the operation of the machine and ensure efficiency, safety, and economy of the operation. This extracted information has been characterized by six morphological features of particle shape, edge curvature, size, color, thickness ratio, and surface texture. These features are the building blocks in the creation of image analysis systems to supplement the wear judgments made by experts who use traditional methods of diagnostics. The paper investigates one of the six morphological features related to the surface texture classification of wear particles. Image processing procedures of line/edge detection and Artificial Neural Networks are used to recognize four texture types of smooth, pitted, striations, and rough. An accuracy classification rate of approximately 98.9% has been achieved and is shown by a confusion matrix.