Porosity Percentage Research Articles

Enhancing Dry Sliding Wear Resistance of Pure Mg by Plasma Electrolytic Oxidation Ceramic Coatings Using Silver Addition

This study investigated the wear effect on ceramic coated Mg by Plasma Electrolytic Oxidation. Three series of PEO coatings were prepared; one of was the effect of silicate electrolyte (5, 8, and 10 g/L) concentrations and the other was the effect of coating time (5, 10, 15 min), last one was the effect of AgNO3 (0.1, 0.2, 0.4 g/l) additive. The coatings were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The mechanical properties were analyzed by microhardness and linear wear test. The unlubricated wear resistance was observed by linear ball-on-disc tribometer. With increasing the silicate concentration, the average pore size and porosity percentage and the surface roughness increase. On the other hand, with increasing the coating time, the surface morphology gradually becomes flat. The coating time caused more compact and homogenous appearance. The surfaces coated with the addition of silver were obtained smoother and denser. The wear resistance of the high time coated Mg was significantly improved. The best wear resistance was obtained with silver-reinforced coatings.

Nanofiber/hydrogel composite scaffolds based on alginate sulfate and extracellular matrix for cartilage tissue engineering applications

In this study, a three-layer composite scaffold was fabricated based on co-electrospun polycaprolactone/gelatin (PCL/GT) and polyvinyl alcohol/gelatin sacrificial nanofiber, alginate/alginate sulfate hydrogel and decellularized extracellular matrix powder. The novelty of this study is the fabrication of co-electrospun PCL/GT and polyvinyl alcohol nanofibers, which are modified by the sacrificial agent method, alginate/alginate-sulfate hydrogels, and DECM powder as growth factors with the aim of cell infiltration. Comparing the results of the microscopy images of the co-electrospun nanofibers before and after the washing process revealed that the distance between nanofibers increased from 2 ± 0.3–8 ± 0.1 µm. Furthermore, an increase in the porosity of prepared nanofibers by the washing process was observed. In addition, cell morphology studies showed that after 7 days, the cells could penetrate the underlay of nanofibers. Decellularized extracellular matrix powder in a hydrogel medium improved cell adhesion. The scaffold's porosity was tested to evaluate the ability of the cells to penetrate. The results showed that the percentage of porosity in optimized nanofiber is 94.4 ± 1.4%, which increased by 14% compared to PCL/GT with the conventional electrospinning method. Moreover, by preparing the optimal multi-layer composite, the porosity percentage was about 93.3 ± 1%. Finally, to investigate cell infiltration, cell seeding was performed on the optimal multi-layer composite for 7 and 14 days. H&E and DAPI staining analysis demonstrated that the cell penetration process through the optimal nanofiber layer was successful.

Enhancing mechanical and functional properties of LM25 alloy through squeeze cast hybrid nanocomposite incorporating breadfruit seed husk ash and graphite nanoparticles

ABSTRACT In this research, effective utilization of agro waste breadfruit seed husk ash particle (SHA) as reinforcement purpose in LM25 alloy matrix enhanced with the inclusions of 3, 6, and 9wt% of graphite (Gr) nanoparticle (50nm) via squeeze cast liquid processing executed with 200MPa applied compressive pressure. This developed cast examined LM25 alloy and its composites for density, percentage of porosity, microstructure, ultimate tensile strength, abrasion, and corrosion behaviour. From the experimental result, the LM25/10wt% SHA/9wt% Gr hybrid nanocomposite has low density (2.554g/cc), an excellent ultimate tensile strength of (181±1.8 MPa), superior abrasion resistance (0.332mg/m) under 40N load at 0.75m/sec, and good corrosion resistance (0.00382mm/year) compared to cast LM25 alloy. The inclusions of SHA and Gr proved their presence in LM25 alloy has good mechanical strength and maximum abrasion and corrosion resistance to overcome the drawbacks of conventional stir-casted LM25 alloy, which is poor wear resistance.

Effect of Rolling at Moderate Temperature on Mechanical and Physical Behavior of the Light Weighted Composite Materials

An application of the light weight martials play the significant role in the modern industries. Such materials along with the high strength to weight ratio and significant mechanical attributes utilized to fabricate the new generation materials for automobile industries. Al and its alloy have been utilized widely in the current automotive industries, especially addition of silicon in aluminium alloy provide significant improvement in Mechanical and physical properties. In the current study Al-Si alloy has been utilized as a base material to prepare the composite materials along with graphite powder. Fabricated materials have been characterized and evaluate the effect of rolling at moderate temperature on mechanical and physical properties. It has been found that the composite's material hardness have significant with respect to rising thickness reduction. The density of the materials continuously increases with increasing the percentage of thickness reduction and porosity reduced.

Additive Manufactured Parts Produced Using Selective Laser Sintering Technology: Comparison between Porosity of Pure and Blended Polymers.

For different manufacturing processes, porosity occurs in parts made using selective laser sintering (SLS) technology, representing one of the weakest points of materials produced with these processes. Even though there are different studies involving many polymeric materials employed via SLS, and different manuscripts in the literature that discuss the porosity occurrence in pure or blended polymers, to date, no researcher has reported a systematic and exhaustive comparison of the porosity percentage. A direct comparison of the available data may prove pivotal in advancing our understanding within the field of additively manufactured polymers. This work aims to collect and compare the results obtained by researchers who have studied SLS's applicability to different amorphous or semi-crystalline polymers and pure or blended materials. In particular, the porosity values obtained by different researchers are compared, and tables are provided that show, for each material, the process parameters and the measured porosity values.

The Impact of Microscopic Pore Network Characteristics on Movable Fluid Properties in Tight Oil Reservoir

The fluid flow behavior, generally referred to as seepage, could determine the hydrocarbon and brine movement behavior. Movable fluid property, as one of the vital parameters for seepage characteristic evaluation, was generally used for tight oil reservoirs’ fluid flow ability assessment. The nuclear magnetic resonance technique was used to experiment with movable fluid percentage and movable fluid porosity, which can provide a realistic assessment of the amount of fluid that can flow in the porous media. Other techniques were also used to analyze the main factors in regulating the differences in movable fluid parameters. However, the research about fluid flow behavior was generally based on traditional methods, while the seepage characteristics from the pore-scale view are still a myth. To promote this process, in this study, core samples obtained from the Chang 7 reservoir of the Triassic Yanchang Formation in the Longdong region of Ordos Basin, China, were tested. The results show that the average movable fluid percentage and average movable fluid porosity of the total 16 core samples are 36.01% and 2.77%, respectively. The movable fluid exists mainly in the midlarge pores with the corresponding T 2 relaxation time over 10 ms. T 2 distributions mainly present four typical patterns: (1) bimodal distribution with similar amplitudes of the two peaks (occupying 6.25%), (2) bimodal distribution with higher right peak and lower left peak (occupying 18.75%), (3) bimodal distribution with higher left peak and lower right peak (occupying 56.25%), and (4) unimodal distribution (occupying 18.75%). Pore structure heterogeneity is closely related to the movable fluid parameters; the movable fluid parameters exhibit a relatively good correlation with core throat radius as well as permeability. There is an obvious difference between the movable fluid parameters and the microscopic characteristic factors in tight oil reservoirs due to the difference in physical properties, clay mineral content, microcracks, and pore structure characteristics. This research has provided a new perspective for the movable fluid property evaluation, and the relevant results can give some advice for the oil field development.

Investigations on Compaction Behavior of Kollidon®SR-Based Multi-component Directly Compressed Tablets for Preparation of Controlled Release Diclofenac Sodium.

The physics of tablets mixtures has gained much attention lately. The purpose of this work is to evaluate the compaction properties of Kollidon® SR (KSR) in the presence of different excipients such as Microcrystalline cellulose (MCC), Monohydrous lactose (MH Lactose), Poly (vinyl acetate) (PVA100), and a water-soluble drug Diclofenac sodium (DNa) to prepare once daily formulation. Tablets were prepared using direct compression and were compressed into flat-faced tablets using hydraulic press at various pressures. The combination of MCC and KSR in the tablets showed reduced porosity, and almost constant low Py values as KSR levels increased; also, KSR-DNa tablets had higher percentage porosity and crushing strength values than KSR-MH Lactose tablets. The crushing strengths of KSR-MCC tablets were larger than those of KSR-DNa tablets. Ternary mixture tablets comprised of KSR-MCC-DNa showed decreased porosities and low Py values as the percentage of KSR increased especially at high compression pressures but had higher crushing strengths compared to KSR-DNa or MCC-DNa binary tablets. KSR-MH Lactose-DNa ternary tablets experienced lower porosities and crushing strengths compared to KSR-MCC-DNa tablets. Quaternary tablets of KSR-PVA100-MCC-DNa showed lower porosity and Py values than quaternary tablets obtained using similar proportion of MH Lactose instead of MCC. In conclusion, optimum quaternary tablets were obtained with optimum crushing strengths, relatively low Py, and moderate percentage porosities among all prepared quaternary tablets. The drug release of the optimum quaternary tablets demonstrated similar in vitro release profile compared to that of the marketed product with a mechanism of release that follows Korsmeyer-Peppas model.

Corrosion and Tribological Studies on Additively Manufactured Gyroid Ti-6Al-4V with Varied Porosity Percentage for Orthopaedic Application

Corrosion and Tribological Studies on Additively Manufactured Gyroid Ti-6Al-4V with Varied Porosity Percentage for Orthopaedic Application

Size-Dependent Frequency Analysis of Higher-Order Microplates with FGP Core and Polymeric CNTRC Faces Considering Piezoelectricity

The present study examines a microplate with a porous structure and two nanocomposite piezoelectric layers. All the layers’ properties are graded functionally, bonded to each other, and supported by an elastic foundation that can withstand both normal and shear loads. Additionally, carbon nanotubes are used to increase the electro-mechanical performance of the piezoelectric patches, which are exposed to an externally applied electric voltage. Using a higher-order trigonometric shear deformation theory and von Karman’s assumptions, the kinematic relations are demonstrated. The governing motion equations are derived using Hamilton’s principle and variational technique, and the modified couple stress theory is employed to take the scale effect into account. An analytical method based on Fourier series functions is used to solve the differential motion equations, and the impact of diverse factors such as porosity percentage, pore distribution patterns, carbon nanotubes distribution patterns, and other key parameters on the normalized frequencies of the model is analyzed after verifying the accuracy of the results. The findings of this research may aid in the development and production of smart structures and devices with increased efficiency.

Elecrospun nanofibers: The versatile platform as a drug delivery system in healthcare

Nanofibers are fabricated using several polymers, carbon, and semiconductors having cross-sectional diameter less than 100 nm. The exceptional state-of-art 3-D architecture and remarkable physico-chemical characteristics of nanofibers have found versatile applications in various fields. This review provides insights into preparation methods and applications of nanofibers. Nanofibers may be prepared by several methods like electrospinning, self-assembly, phase separation, anti-solvent induced polymer precipitation, etc.; however, electrospinning is the mostly employed technique for nanofibers fabrication. Electrospinning is known to be an electrohydrodynamic process in which a liquid droplet is electrically charged, resulting in the formation of a jet, which is then stretched and elongated to produce fiber(s). The nanofibers have an enormous surface area to volume ratio, resulting in a high percentage of porosity of nanofibrous mats. These characteristics allowed higher drug loading, especially biological macromolecules albeit of their large molecular size. Hence, the nanofibers fetched attention for their application in the healthcare and biomedical engineering sector for the treatment and management of diabetic foot ulcers, cancer, microbiological disorders, wound healing, and cardiovascular diseases. Additionally, nanofiber mats possess a 3-D architecture as well as nanofibers can either be oriented randomly or in an ordered fashion for tissue engineering-related drug delivery applications. The above-mentioned peculiarities enables nanofiber scaffolds to mimics human tissues and hence are being explored for their applications in tissue engineering, artificial organ, filtering aids for microbes, cosmeceutical industry, etc. Conclusively, the nanofibers can serve as an excellent drug delivery and tissue-engineering platform for the treatment in healthcare.

Improvement of the performance characteristics, fire resistance, anti-bacterial activity, and aggressive attack of polymer‐impregnated fired clay bricks-fly ash-composite cements

The research addressed the creation of various composite cement mixes by replacing 40 % of OPC with industrial solid wastes, Fly ash (FA), and/or Fired clay bricks (FCB) at different water/powder (w/p) ratios. The composite cement pastes were subjected to polymer-impregnation process, using methyl-methacrylate (MMA) monomer and benzoyl peroxide as an initiator. The physico-mechanical and chemical characteristics of the polymer-impregnated specimens, such as compressive strength, bulk density, total porosity, and polymer load, were examined. The findings showed that, as compared to neat pastes (PF1, PF2, and PF3), the compressive strength (CS) of mixes (PFH1, PFH2, and PFH3) rose considerably after 3 months of hydration by 10.53 %, 12.82 %, and 28.85 %, respectively. Additionally, mix PFH1 with a water/powder (w/p) ratio of 0.35 exhibited the greatest bulk density value (2.215 g/cm3) and the lowest total porosity percentage (12.72 %). Data demonstrated that polymer-impregnation is efficacious to strengthen constructions subjected to high temperatures and aggressive salt attacks. The study additionally revealed that, when thermally treated at 200, 400, and 600 °C, respectively, the CS of PFH1 paste increased by 1.44 %, 1.78 %, and 1.48 % after 14 days of curing, but increased by 10.85 %, 5.20 %, and 7.89 % at curing time of 28 days. Likewise, when CS was compared to that before to polymer-impregnation up to three months, it grew by 48.53 % following immersion in 5%-MgSO4 solutions but increased by 13.49 % after immersion in 5%-MgCl2 solutions.Moreover, the composite with a water/powder ratio of 0.45 demonstrated remarkable anti-bacterial activity against both Gram-negative and Gram-positive bacteria. In conclusion, the study shows that the compressive strength, antibacterial activity, fire resistance, and resistance to aggressive attacks of the composites are all improved by MMA polymer impregnation.

Effect of Rolling at Moderate Temperature on Mechanical and Physical Behavior of the Light Weighted Composite Materials

Abstract: An application of the light weight martials play the significant role in the modern industries. Such materials along with the high strength to weight ratio and significant mechanical attributes utilized to fabricate the new generation materials for automobile industries. Al and its alloy have been utilized widely in the current automotive industries, especially addition of silicon in aluminium alloy provide significant improvement in Mechanical and physical properties. In the current study Al-Si alloy has been utilized as a base material to prepare the composite materials along with graphite powder. Fabricated materials have been characterized and evaluate the effect of rolling at moderate temperature on mechanical and physical properties. It has been found that the composite's material hardness have significant with respect to rising thickness reduction. The density of the materials continuously increases with increasing the percentage of thickness reduction and porosity reduced.

Investigation on effect of carbon equivalent and inoculation on the solidification and shrinkage tendency of ductile cast iron using thermal analysis

PurposeThe foundry industry incurs additional costs as a result of defective castings. Shrinkage defects are a frequent problem in ductile iron castings. It is still essential to understand how shrinkage porosity varies in size when the ductile iron composition changes. This information can be used to produce high-quality cast parts and determine the best processing conditions. The objective of this research paper is to examine the effect of carbon equivalent and inoculation on the morphology of the shrinkage defect using thermal analysis.Design/methodology/approachThis study focuses on certain thermal analysis parameters, such as the angle of the first derivative curve at the solidus temperature, recalescence and its relationships to graphite nucleation and shrinkage tendency. The results of thermal analysis in terms of the cooling curve and its derivative parameters, and thorough characterizations of the shrinkage observed in cup castings produced with various melt compositions and inoculation are presented in the current study.FindingsThe proportion of caved surfaces and macro shrinkage porosity defects has been reduced as the carbon equivalent of melt increases from hypoeutectic to a hypereutectic composition. The composition that is slightly hypereutectic has the lowest shrinkage propensity. Although inoculation reduces shrinkage, the importance of this parameter differs depending on the carbon equivalent.Originality/valueThe percentage of macro shrinkage porosity and the angle that the cooling rate curve forms are strongly correlated. It is found that the macro shrinkage size decreases as the angle of the first derivative curve at the solidus temperature is reduced. Further, lower macroporosity is produced by a metal that has a higher nodule count in association with a greater cooling rate toward the end of the solidification process.

Fuzzy modeling and characterization of mechanical and biological properties of a selective laser melting shape: A comprehensive study

The bone scaffold is a porous structure that possesses suitable biological and mechanical properties similar to those of natural bone, thereby providing a suitable substrate for bone growth. The scaffold plays a temporary role in the bone repair process and is composed of degradable material that gradually degrades over time to enable new bone growth and replacement. The scaffolds are implanted using bone morphogenetics of transplanted bone-protein (BMP-7) and implanted subcutaneously to assess biological properties and tissue growth. This study demonstrates the ability to design and fabricate a titanium scaffold with a porous architecture using the Selective Laser Melting (SLM) method, employing two different geometries. The scaffolds' mechanical properties are assessed via a compression test, and the results are utilized for finite element analysis (FEA), predicting the designed metallic scaffold's optimal geometric shape and porosity percentage. The biological response of the scaffolds is evaluated via simulated body fluid (SBF) and phosphate buffer saline (PBS) analyses. The findings indicate that the 8-sided scaffold has superior mechanical and biological features compared to the circular and 6-sided geometries. To predict the scaffold's specifications before conducting the experiment, a fuzzy modeling system is used to model the effect of inputs such as weight percentage, elastic modulus, porosity, and Poisson ratio on the compressive strength output variable.

Enhanced knee joint treatment using a hybrid hyaluronic acid-alginate filler reinforced with hydroxyapatite-titanium nanoparticles for sports-related injuries

Sports injuries, particularly bone injuries, have become increasingly prevalent in recent years. As athletes push themselves harder and become more competitive, the risk of injury rises. Additionally, the aging population has contributed to the increased prevalence of bone injuries, including those related to the knee joint. As a result, significant research efforts have focused on developing new techniques for knee joint repair. In this study, a novel hyaluronic acid-Alginate filler composition containing hydroxyapatite-titanium nanoparticles (HA/Ti-NPs) was prepared through freeze-drying. The crystalline properties of the porous scaffolds were analyzed using X-ray diffraction (XRD), while scanning electron microscope (SEM) images were used to visualize the scaffold structure. The morphological investigation demonstrated that adding 15 wt% Ti-NP to the scaffold reduces percentages of porosity to about 76.5 ± 5, while increasing the elastic modulus. Furthermore, the presence of nanoparticles decreased the rate of degradation, increased crystallinity, reduced pore size, and promoted calcium release, creating a favorable environment for bone tissue growth. The scaffold's degradation pH is close to neutral, which is ideal for bone tissue treatment. Adding 15 wt% Ti-NP reduces the contact angle from 120° to 93°. The composite scaffolds promote the proliferation and growth of osteoblast cells, and after 48 h, degraded material improved cell viability, growth, and proliferation. The three-component hyaluronic acid-Alginate/HA scaffolds with 15 wt% Ti-NP exhibited suitable morphological, mechanical, physical, and chemical properties for bone applications, as well as high potential for joint bonding. These porous scaffolds have the potential to be used as bone fillers of sport injuries and further research is needed to confirm their efficacy.

The Effect of Lime Stone in the Probability of Formation Pores Structures in Glass Ceramic Based on Scoria Basalt Rocks

This paper provides a Lightweight material is the result of technological problems in increasing the efficiency of finished products, saving manufacturing costs and environmentally friendly technology by reducing the amount of material used. There are many kinds of material manufacturing technology, ranging from the use of lightweight materials from the start, combining materials into composites and modifying the structure and characteristics of the material to make it lightweight. One commonly used method is to mix glass-ceramic with a foaming agent in purpose to modify the structure of material. The purpose of this study is to utillize basalt rock as source of glass ceramic and mixed with limestone to form cellular structure with optimal composition. The samples was crushed and sieve through 100 mesh afterward all material is mixed varied between basalt and lime with a ratio of sample A (100% Basalt), sample B (3:7), sample C (5:5), and sample D (7:3), which were burned at a temperature of 1100°C and 1300°C. After all sample reach designated temperature, all sample undergo annealed cooling in the furnace. Based on the characterization results, the best glass-ceramic sample formed with pores structure formation was sample B which is 70% addition of limestone in basalt mixture and burned at a temperature of 1100°C with a total pore size of 63% and a density of 0.92 g/cm3, where the glass-ceramic structure detected pyroxene and lime phases with a SiO2 composition of 14.61%. Basalt cellular ceramic is obtained in optimal condition with low density and higher percentage porosity.

Diagenesis as a control on the tight sandstone reservoir quality of the upper Carboniferous strata in the northeastern Ordos basin, China

The upper Carboniferous tight sandstone strata are considered the most promising targets for gas exploration in the northeastern Ordos Basin. Reservoir quality is critical for the successful commercial exploration and development of tight sandstone gas. Reservoir quality of deeply buried tight sandstones is controlled by diagenesis, yet there is sparse systematic documentation on upper Carboniferous tight sandstone reservoir quality and its diagenetic link. In this study, we utilized core analysis and wireline log data, and core samples were studied using X-ray diffraction, optical light microscopy, scanning electron microscopy, porosity–permeability, mercury intrusion capillary pressure and nuclear magnetic resonance measurements. Dolomite, siderite, quartz, kaolinite, and illite are the main diagenetic cements. The upper Carboniferous sandstones pore system consists of residual intergranular pores, intragranular dissolution pores associated with feldspar grains and micropores mainly related to diagenetic minerals. Due to differences in diagenetic alterations, sandstones have significant differences in pore types and pore-filling components, ultimately leading to differences in reservoir quality. The residual intergranular porosity is closely related to the reservoir quality. Quartz cement and authigenic clay minerals lead to reduced residual intergranular porosity, but their impact on reservoir quality is relatively limited due to their relatively low content. The most significant factors contributing to reservoir quality deterioration are ductile (clay-rich) grain-influenced compaction and pervasive pore-filling carbonate cement. When sandstone contains large numbers of ductile grains, it loses a large amount of intergranular porosity due to compaction, and the pore space contains only a small number of dissolution pores and micropores, resulting in reservoir quality deterioration. Similarly, when a large amount of carbonate cement is developed in sandstone, it leads to intergranular porosity loss. The best reservoir quality sandstones preserve a percentage of intergranular porosity because they (i) have few ductile grains, resulting in low compaction, and (ii) do not have significant amounts of carbonate cements. Finally, the diagenetic variations were successfully correlated with wireline logs to evaluate the reservoir quality of subsurface upper Carboniferous sandstones. The data sets provided in this research offer insights to better evaluate and predict reservoir quality in the northeastern Ordos Basin.

Entropy analysis and mixed convection of nanofluid flow in a pillow plate heat exchanger in the presence of porous medium

A pillow plate heat exchanger (PPHE) is one of the types of heat exchangers that haven't received the attention they deserve despite their high efficiency and operational capability. A unique feature of PPHEs is their pillow-shaped structure, which is achieved through hydroforming. In light of this, scholars have been interested in analyzing and optimizing the thermo-hydraulic properties of PPHEs. In this study, the interior of the PPHE was occupied with a permeable substance with a high porosity percentage (0.9034 ≤ ɛ ≤ 0.9586 and 0.00015 ≤ dp ≤ 0.00065) and saturated with Ag-water (0 ≤ϕ ≤ 0.06) nanofluid, which has a profound influence on the heat transfer rate of PPHEs. In order to analyze the determinants affecting the heat transfer rate of PPHEs under these conditions, the governing equations were solved using the finite volume method and also the Brinkman-Forchheimer-extended Darcy equation. According to the results, heat transfer is enhanced in PPHE when using a permeable medium with high porosity and a small pore size. That is, PPHEs transfer heat more efficiently when they are placed in a denser porous medium because heat conduction is boosted. Moreover, due to the increased thermal conductivity of the nanoparticles, the application of nanoparticles to the base fluid also enhanced heat transfer and Nusselt number. However, decreases in friction factor and entropy generation were observed with increasing porosity, pore size, and Darcy number, due to reduced flow resistance. A decrease in Richardson number also results in a decrease in friction factor and entropy generation. At the wake region of welding spots, the velocity has reached its lowest values; consequently, this led to a reduction in the heat transfer rate. Nevertheless, within dense porous media, at the lower hydraulic diameter points, the conduction contributes to heat transfer improvement. The porous medium acts as a heat sink and absorbs the heat from the welding spot. This allows the heat to be dissipated away from the welding spot, which reduces the velocity and heat transfer rate. The nanofluid, on the other hand, helps to increase the thermal conductivity of the medium, resulting in more heat being transferred to the surrounding material. Consequently, the results demonstrated that PPHEs' thermal and thermodynamic performance could be significantly improved by using a porous medium saturated with nanofluid.

Multi-parametric optimization volumetric porosity to minimize energy consumption in high-rise residential complexes

The physical characteristics of high-rise buildings are among the complex and influential factors that contribute to energy consumption reduction. This research introduces an algorithmic method to investigate the impact of volumetric porosity of buildings on the level of cooling and heating load consumption. The objective of this research is to elucidate the correlation between the aforementioned variables in a high-rise residential complex in Tehran city through a proposed method. This objective was accomplished through the creation of a parametric and variable “Modular Generative Model”. To this end, a parametric generative model was utilized to extract models with varying porosity percentages. These models were then influenced by the percentage of surface radiation in Tehran on two specific dates: the summer solstice and the winter solstice. The extraction process was performed algorithmically. Then, a multi-parametric simulation was conducted on these two dates, considering various parameters, in a way that can be generalized to other global climates. The correlation between the pore volume percentage and the energy consumption was calculated and tested on the aforementioned dates.In the subsequent phase, energy simulation was carried out once again to optimize energy consumption for a specific climate. This involved replacing the glass modules with porous modules in the mentioned samples and leveraging their greenhouse effect. Subsequently, the correlation between the greenhouse effect and the cooling and heating load consumption was analyzed by studying the correlation graph. Finally, in order to achieve the optimal solution, a genetic algorithm was employed to determine the optimal values of the independent variables, which would result in the minimum values of the dependent variables. The findings of this research provide a set of quantitative recommendations based on the most optimal solution, which can be utilized as form-finding rules in the initial stages of design.

Analyzing the microstructure of cemented fills adding polypropylene-glass fibers with X-ray micro-computed tomography

Fiber reinforced cementitious tailings backfill (FRCTB) is progressively employed in mining industry due to its high strength/stiffness-to-weight ratio. However, the wide use of the FRCTB technique requires further study of the practice of many different types of fibers, either alone or in combination. In this regard, this paper explores the impact of composite (glass-polypropylene) fibers on microstructure of FRCTBs considering weak surface and pore characteristics. The fractures of backfills were quantitatively analyzed by a non-destructive X-ray micro-computed tomography system which permits imagining of the interior microstructures of backfills via the construction of 3D volumetric data in diverse spatial scales. Quantitative parameters cover percent weak surface, porosity, and pore sphericity. The spatial distribution of weak surfaces, pores, and fissures and the bridging effect of fibers were also analyzed based on the 3D reconstruction technique. Adding fibers increased the percentage of FRCTB's weak surface. The greater the glass fiber dose, the larger the percentage of the weak surface. Composite fibers can lessen FRCTB's porosity. The smallest FRCTB porosity was 0.07 % for glass and PP fiber contents of 0.4 wt% and 0.2 wt%, respectively. A rise in glass fiber dose causes a rise in volume of 10–100 mm3 pore content. Fibers have a greater impact on the volume of 0.1–100 mm3 pores, and the rise in glass fiber dose deteriorates shape of this type of pores, leading to a reduction in the sphericity of this type of pores. There is a clear correlation between the distribution patterns of weak surfaces, pores, and fissures along the height of the specimens. Weak surfaces and pores are prone to develop as fractures. Fibers can limit the crack expansion in FRCTB. Lastly, this study presents a time- and cost-saving method for analyzing FRCTB's microstructure.