Simple Compression Research Articles

All-Inclusive Sensing Tablet with Integrated Passive Mixer for Ultraviscous Solutions.

Developing low-cost and easy-to-use point-of-care devices is necessary for timely disease diagnosis and health monitoring. Here, we introduce all-inclusive, tablet-based chemo/biosensors with rapid automixing features, capable of mixing in highly viscous solutions with viscosities up to 1700 mPa·s. These tablets are created using a simple powder compression method and contain all necessary reagents to perform assays in a "drop-and-detect" manner, without the need for vigorous shaking or vortex mixing. As proof of concept, we demonstrated the applicability of our Speedy tablets for detecting nitrite in human saliva, a challenging medium due to its viscosity. The strong mixing capability of the proposed tablets ensured consistent and reliable results across range of viscosities, from low to high, while delivering an excellent detection range of 0.03-1.50 mg/dL, covering nitrite levels in human saliva. Additionally, we developed a straightforward method to encapsulate enzymes in trehalose, making them bulkier and more stable using only a mist sprayer, nonstick tray, and spatula, eliminating the need for expensive equipment. This approach allowed us to incorporate small amounts of enzymes into tablet formulations and fabricate the first automixing tablet biosensor. These biosensors were used for the bienzymatic detection of glucose in real human urine within the biologically relevant range of 0.3-2.5 mM, indicating the compatibility of automixing tablets with bioreagents. Each tablet costs less than $0.30 to produce and remains stable for at least one month at room temperature. The affordability and convenience of our tablets make them a valuable addition to the array of diagnostic tools.

∆DHT-Zip: A Delta-difference Hybrid Tree Coding Scheme for End-to-end Packet Compression Framework in Network-on-Chips

Due to the maximal transistor count, Multi-Processor System-on-Chip (MPSoC) delivers more performance than uniprocessor systems. Network on Chip (NoC) in MPSoC provides scalable connectivity compared to traditional bus-based interconnects. Still, NoC designs significantly impact MPSoC design as it increases power consumption and network latency. A solution to this problem is packet compression which minimizes the data redundancy within NoC packets and reduces the overall power consumption of the whole network by minimizing a data packet size. Latency and overhead of compressor and decompressor require more memory access time, even though the packet compression is good for the improved performance of NoC. So, this problem demands a simple and lightweight compression method like delta compression. Consequently, this research proposes a new delta-difference Hybrid Tree coding (∆DHT-Zip) to de/compress the data packet in the NoC framework. In this compression approach, the Delta encoding, Huffman encoding and DNA tree (deoxyribonucleic acid) coding are hybridized to perform the data packet de/compression approach. Moreover, a time series approach named Run Length Encoding (RLE) is used to compress the metadata obtained from both the encoding and decoding processes. This research produces decreased packet loss and significant power savings by using the proposed ∆DHT-Zip method. The simulation results show that the proposed ∆DHT-Zip algorithm minimizes packet latency and outperforms existing data compression approaches with a mean Compression Ratio (CR) of 1.2%, which is 79.06% greater than the existing Flitzip algorithm.

THE NASAL SEPTUM HEMANGIOMA: A CASE REPORT

Hemangiomas are fast-growing, pseudotumours of vascular origin, secondary to hyperplastic proliferation of endothelial cells, with no capacity for degeneration. They can be classified as capillary, cavernous and mixed according to their histopathological features. Although hemangiomas of the head and neck are common, those of the nasal cavity and paranasal sinuses are extremely rare and may manifest as recurrent epistaxis and progressive nasal obstruction (unilateral). We report the case of a 47-year-old female patient who presented with a history of recurrent epistaxis of moderate severity on the right side over the past few months, with progressive onset of right nasal obstruction. These episodes resolved spontaneously after simple bidigital compression. Rhinoscopy performed at the beginning of the consultation revealed an anterior fleshy mass at the level of the right nasal septum obstructing the nasal cavity (Figure 1). Nasofibroscopy showed no other abnormalities, particularly in the nasopharynx. A nasosinusal CT scan (see Figure 2) performed after contrast injection revealed a hypervascular mass in the anterior part of the nasal cavity at the level of the right anterior nasal septum in contact with the inferior turbinates (see Figure 2). Surgical excision was performed by endonasal endoscopy with no postoperative complications.

Management of extremity and pelvic fractures in earthquake: our observations and recommendations

BackgroundEarthquakes frequently cause injuries to the musculoskeletal system. Studies conducted after earthquakes often report on injured limbs, fractures, and surgeries. This study aimed to enhance preparedness for future earthquakes by acquiring knowledge about the prevalence of fractures and the relationship between fracture types and injury mechanisms.MethodsA retrospective analysis was conducted on medical records of patients with fractures admitted to our hospital following the 2023 Kahramanmaraş Earthquake. Patients with fractures resulting from traffic accidents or other causes unrelated to earthquakes were excluded. The recorded data included age, gender, fracture site, fracture type, mechanism of injury, date, duration of surgery, and peak creatine kinase (CK) level. The injury mechanisms were classified into four main categories: injured by falling objects, falling while running, falling from height, and being trapped under rubble. The study investigated the relationship between fractures and other factors.ResultsThe study included 185 patients with a mean age of 39.62 ± 20.83 years. The most frequent mechanism of injury was being trapped under rubble. In total, there were 214 fractures, with pelvic fractures being the most common (21.50% of all fractures). Tibia fractures were the most common fractures in the lower extremities (15.89%). Women had a significantly higher occurrence of pelvic fractures (33.3%) compared to men (14.5%) (p = 0.003). The frequency of pelvic fractures significantly increased as age decreased (p = 0.007). Patients with pelvic fractures had a significantly greater peak CK concentration (p = 0.006). Open fractures were more common in the first few days, and Kirschner wires were the first treatment applied at a mean of 74 h and external fixators at a mean of 94.3 h.ConclusionInjuries from falling objects from roofs and jumping from heights are important in earthquakes. In addition to lower extremity fractures, pelvic fractures are common in earthquake disasters. Most pelvic fractures are simple lateral compression fractures and it is important to follow the patients for crush syndrome in the first days instead of focusing on definitive fracture treatment. Open fractures should be prioritized for fracture surgery within the first few days. External fixators and Kirschner wires are recommended. Closed fractures should be treated conservatively and definitive surgical procedures should be postponed to the following weeks.

Study on mechanical properties of polyurethane elastomers in different strength tests

Elastomeric materials are used in the methods of plastic forming of sheets made of difficult-to-deform materials. This article presents the results of strength tests of selected elastomeric materials intended for sheet metal stamping. Polyurethane elastomers with a hardness of 50, 70 and 90 Sh A were used for the tests. The behaviour of the materials was determined in a simple compression test, a volumetric compression test and a uniaxial tensile test. In the case of the simple compression test, the values of the maximum force for a set punch travel of 3 mm were 1400 N, 2250 N and 4950 N for samples with hardnesses of 50, 70 and 90 Sh A, respectively. In a volumetric compression test, the maximum compressive force for a sample with a hardness of 90 Sh A was more than twice lower than the compressive force of samples with a hardness of 50 and 70 Sh A. In the tensile tests, the values ​​of the obtained strains ranged from about 750% for the sample with a hardness of 50 Sh A to about 1350% for the sample with a hardness of 90 Sh A.

Study of the relationship between uniaxial compressive strength and the indirect tensile test (BTS) in rocks from the bank in Seybaplaya Campeche Mexico

The present research focuses on analyzing the uniaxial compressive strength of rocks and its relationship with the indirect tensile test (the Brazilian method). It is important to note that Seybaplaya, located in Campeche, Mexico, is known for its fishing, industrial and commercial activities, and is home to a rock bank from which samples were obtained for this study. As a result, an equation was developed that allows predicting the simple uniaxial compressive strength from the values obtained in the indirect tensile test. It should be noted that this relationship is valid only for rocks with similar lithological characteristics of the samples analyzed. The results of the analysis and conclusions show the linearity of the relationship between the simple uniaxial compression resistance and the indirect tensile test.

Analysis of a simple vapor compression and ejector refrigeration systems working with eco-friendly refrigerants

Transitioning to alternative refrigerants with low Global Warming Potential (GWP) in both vapor compression and ejector refrigeration systems emerges as a viable strategy to address the environmental impact associated with refrigeration technologies. This shift necessitates a thorough examination of factors such as thermodynamic performance, safety considerations, and optimization of system design. The outcomes of this study contribute to the advancement of sustainable refrigeration systems, aligning with global initiatives to curb greenhouse gas emissions and preserve the environment. The study adopts a thermodynamic approach to numerically investigate several eco-friendly refrigerants with GWP below 150, including R1234yf, R1234ze, R1270, R152a, R290, and R600a, as potential alternatives for vapor compression and ejector refrigeration systems. Thermodynamic models, developed in MATLAB using refrigerant properties, reveal that R600a and R290 exhibit promising potential as replacements for R134a in vapor compression refrigeration systems. These alternatives demonstrate a noteworthy improvement in the thermodynamic coefficient of performance, with percentages of 2.47% and 2.12%, respectively, under similar working conditions. For ejector refrigeration systems, R152a, R717, and R1270 exhibit enhanced coefficients of performance, contributing to significant savings in generator heat load. The results highlight the ability of these refrigerants to improve both the efficiency and sustainability of refrigeration systems in diverse applications.

Development and Evaluation of Gastroretentive Floating Bilayer Tablets Containing Ivabradine hydrochloride and Trimetazidine dihydrochloride

Introduction: Unlike conventional angina treatment medicines, newer antianginals such as Ivabradine hydrochloride and Trimetazidine dihydrochloride displayed therapeutic potential without negative effects. However, IBH and TMZ both have shorter half-life and require multiple dosing. Literature study revealed that bilayer tablet of combination is not available. Hence, the objective of present research was to formulate and evaluate bilayer floating gastroretentive tablets with IBH immediate and TMZ floating release layer. Materials and Methods: Simple direct compression method and floating technique was employed. IBH and TMZ layer developed separately. IBH layer prepared using Avicel-112, Klucel EXF ultra, and Vivasol/Crosscarmelose sodium while TMZ layer developed using Kollidon SR, Benecel K 200 M, and Sodium bicarbonate. Best trials combined for the preparation of bilayer tablet. Tablets evaluated for pre-compression and post-compression parameters, floating time, floating lag time (FLT), total floating time swelling index, and matrix integrity. Results: Melting point, differential scanning calorimetry, and ultraviolet absorbance confirmed the identity and purity of drug. Fourier transform infrared spectrum of active pharmaceutical ingredient and drug mixture with excipients demonstrated the compatibility. IR layer trial I-4 showed passable flow with 3 s of disintegration time in distilled water and 100% drug release within 5 min. Floating layer trial T-8 showed fair flow characteristic, 15 s FLT, >24 h of total floating time and controlled the drug release more than 12 h without burst effect. Discussion: Preformulation study result revealed that the both the drug are pure form and compatible. For immediate release layer, Vivasol (Crosscarmelose) showed best disintegration and combination HPMC K200 M and Kollidon SR polymer with sodium carbonate provided controlled release with low FLT and high total floating time. Conclusion: Based on research findings, it can be concluded that bilayer gastroretentive tablets successfully formulated with IBH as IR layer and TMZ as floating layer. Combination of polymer needed for drug release control with tablet floatability. Hydrophilic polymer Benecel K200 M forms matrix channel which entrap sodium bicarbonate bubbles and tablet become buyant while Kollidon SR and stearic acid contributes in retardation of drug release.

Comparative Electrochemical Analysis of Lithium and Lithium-Indium Alloy in All-Solid-State Battery

Lithium-ion batteries (LIBs) are widely used in a variety of applications due to their high energy and power densities, and long cycle life. With the expanding use of LIBs in electric vehicles and energy storage systems, there is very active research into all-solid-state batteries (ASSBs), which offer greater energy density than traditional LIBs and eliminate the inherent fire hazards. Since most of the detailed reactions involved in the performance and degradation of a battery are temperature-sensitive, so-called thermal activation processes, it is very important to accurately assess whether a battery can have the high performance and low degradation characteristics required under different climatic conditions. To evaluate the electrochemical properties of electrode materials in LIBs, a half-cell is typically constructed with the electrode of interest as the working electrode (WE) and lithium metal as auxiliary electrode (AE). Here, lithium metal is close to an ideal non-polarizable material, has a large capacity, and maintains a constant potential during charge/discharge, so it is widely used as AE material in LIB research. However, several issues arise when lithium is used as AE in ASSBs: Lithium metal undergoes mechanical deformation due to the relatively high internal pressure required to ensure good contact between lithium and solid electrolyte; When in contact with sulfide-based solid electrolytes, which are currently of interest due to their high ionic conductivity, side reaction products can lead to an increase in interfacial resistance; the growth of lithium dendrites, often observed in conventional LIBs, is still unavoidable. These issues all affect the half-cell signal, potentially causing a distorted evaluation of the WE’s characteristics.Lithium-indium alloy is being utilized as AE for ASSB half-cells to replace lithium metal. It exhibits excellent mechanical ductility and maintains a constant reduction potential over a wide stoichiometric range, ensuring excellent contact property and voltage stability. Moreover, it is very easy to fabricate through simple compression at room temperature. Nevertheless, the limited study on its electrochemical properties leaves uncertainty regarding its full functionality as AE for accurate evaluation of WE, particularly in extreme operational conditions. For instance, lithium-indium alloy are primarily based on alloying/dealloying reactions involving solid-state diffusion of lithium, which is generally considered to be a relatively slow process kinetically, while lithium only involves a kinetically favorable plating/stripping process on the surface. Therefore, a comparative analysis of these different reaction mechanisms in terms of kinetics is necessary. This presentation presents a comparative analysis of the electrochemical properties of lithium metal and lithium-indium alloys used as AEs in ASSB half-cells. In particular, the electrochemical properties of lithium-indium alloys with different reaction mechanisms with lithium are investigated over a range of temperatures and current densities, and these differences are discussed from a kinetic point of view. For this purpose, first, using a three-electrode half-cell with lithium or lithium-indium alloy as AE, we compared the electrochemical properties of these two AEs during half-cell operation by interpreting their potential and over-potential changes, and quantifying their detailed resistances. Then, through dc experiments on lithium and lithium-indium symmetrical cells, we identified differences in overvoltage behavior due to differences in their reaction mechanism. In particular, we noted distinct differences in the overpotential behavior of these two electrodes at low temperatures and high current densities. Furthermore, based on the results of a combined dc/ac electrochemical analysis, we derived the overvoltage that dominates the overall overvoltage at each of the two electrodes. Based on these results, we analyzed how the kinetic differences between the two electrodes affect the cathode half-cell signal, in order to derive key considerations for reliable ASSB half-cell evaluation. In this presentation, the advantages and disadvantages of lithium-indium alloy compared to lithium metal as AE will be discussed from a kinetic perspective, focusing on interfacial and bulk resistance (overpotential). Furthermore, methods for utilizing AE to conduct accurate and reliable half-cell tests will be proposed.

Borohydride/Halide and Oxyhalide/Halide Composite Electrolytes for Assbs

New solid Li-ion conductors based on borohydride-halides and oxyhalide/halides composites have been synthesized by mechanochemical reaction. They include LiM(BH4)yX4-y (M = Y, Ce, X = Cl, Br), Li3M(BH4)yX6-y (M = Y, Sm, Er; X = Cl, Br), y LiMOCl4 + (1-y) LiMCl6 + (2y-1) LiCl (M = Nb, Ta; 0.5 < y <1), and LiMOCl4 + LiCl + y Li2O (M = Ta, Nb; 0 < y < 0.8). The kinetics of the mechanical reaction strongly depends on the selection of starting materials, particularly of oxides. The structures of these electrolytes have been analyzed by X-ray diffraction (XRD), Raman, solid-state nuclear magnetic resonance (NMR). The thermal stability has been tested by differential scanning calorimetry (DSC) and thermogravimetric analysis/mass spectrometry (TGA/MS). The basic mechanical properties have also been characterized by using a simple powder compression as well as nanoindentation, and the results compared with theoretical prediction. Depending on whether they are amorphous or crystalline phases, their ionic conductivity varied between 10-5 and 10-2 S/cm at room temperature. The effect of anion composition and the phase composition of the composites on the ionic conductivity has also been investigated by changing the mix ratio of starting materials; LiX and MX3 for LiM(BH4)yX4-y, and LiCl, MX5, M-O/Li-M-O for LiMCl6/LiMOCl4/LiCl and LiMOCl4/LiCl/Li2O composites. Chemical stability, electrochemical stability window, and critical current density have been characterized. Using these solid electrolytes, all solid state batteries have been assembled and the compatibility of the electrolyte with Li or In/Li anode and uncoated (or Nb-coated) NMC cathode, C-rate property, and long term charge/discharge cycle property have been investigated and the results will be presented.

Effect of adding dune sand to tuff in Saharan road construction

The south region of Algeria is characterized by a wide surface, a scattered population and a very small ratio of road length per habitant. To allow the development of agricultural, industrial and touristic activities between different cities in the south of Algeria, it is necessary to maintain and to develop the road infrastructure. However the development of these infrastructures necessitates the use of huge amount of certified aggregates from quarries which is not available in the vicinity of the need. For these raisons, in the framework of sustainable development, a strategy which consists in using local materials like fine sediments (dune sand) and other types of material is engaged. The materials constituting the road layers, until today, have been limited to certain so-called noble materials (gravel, aggregates, etc.), but these are being depleted as a result of the intensive exploitation and the scarcity of quality careers. Gypso-limestone encrustation tuffs, the most used materials in pavements (base course and base course) in the Saharan areas such as southern Algeria, have shown acceptable behavior for many years until these last days, when this type of material begins to present certain limits under the effect of the intensity of the traffic. In order to promote the abundant wind sands in these regions, we are interested in developing the dune sands in the pavement as a mixture with the tuffs. The present work presents a contribution to the study of the behavior of the tuff of the Adrar region (South of Algeria) alone and mixed with the sand dunes in different formulations. The aim is to evaluate the evolution of mechanical properties including resistance to simple compression, the ability to compaction and punching (RBC). The work also discusses the influence of the addition of cement in low levels on the performance of the mixture.

Validation of thoracolumbar injury classification and Severity Score in the management of acute and subacute Osteoporotic vertebral compression fractures – A pilot study and a suggested modification

ObjectiveTo retrospectively assess the Thoracolumbar Injury Classification and Severity Score (TLICS) in patients with osteoporotic vertebral compression fractures (OVCF) and compare the treatment given with that predicted by the TLICS score. MethodsAll medical records of patients presenting from January 2014 to November 2017 for acute atraumatic or low impact OVCF were screened, and eligible patients were retrospectively reviewed. The TLICS score was determined based upon magnetic resonance imaging (MRI) findings and clinical records. Clinical records (including pain score data), imaging data, operative procedures, and stability of neurological examination were tracked over three months for each patient. ResultsOf the 56 patients included, 36 patients had a TLICS score of 1, 18 had a TLICS score of 2, and two had a TLICS score of 4. Only one patient with a TLICS score of 4 underwent surgical stabilization, while the rest of the cohort was managed non-operatively, with or without kyphoplasty. TLICS score 1 corresponded to simple compression and TLICS score 2 corresponded to burst morphology with retropulsion and without neurological deficits. Of the patients with a TLICS score of 1 and 2 who underwent kyphoplasty, there was a statistically significant improvement in pain scores in both groups; however no significant difference was observed, between each TLICS score (i.e., 1 or 2). None of the patients developed instability or neurological decline. ConclusionTLICS score correctly predicted operative versus non-operative management in all patients with OVCF. TLICS may be used in making management decisions, and in the triage of these patients for operative versus non-operative evaluations. Our study suggests that patients with TLICS score of 4 or higher require surgical evaluation, while those with TLICS of 1 or 2 are likely to have satisfactory non-surgical management with augmentation or conservative care. In general, patients with OVCF typically present with low TLICS score. Kyphoplasty appears to be similarly beneficial in patients with a TLICS score of 1 or a TLICS score of 2. A modification of the TLICS score by adding TLICS Zero to include uncompressed OVCF with edema is suggested. The limitations of this study include a small size; a larger study is needed to confirm these findings.

COMPARATIVE STUDY OF THE MECHANICAL CHARACTERISTICS OF STABILIZED COMPRESSED EARTH BLOCKS: CASE OF STABILIZATION WITH LIME AND CEMENT

This article presents the preliminary results of the comparative study of mechanical characteristics of compressed earth blocks stabilized with cement and lime. This study is relevant to the study of the possibility of replacing cement with lime in the techniques for stabilizing compressed earth blocks. This study, prompted by the concern to reduce the cost of construction, fits well with the policy of promotion and valorization of local construction materials in Benin. This work focuses on the comparative study of the mechanical characteristics of compressed earth blocks stabilized with cement and lime. In this study, we were interested in ferralitic soils called terre de barre wich we will name bar soil stabilized with cement and lime. Identification tests in the laboratory made it possible to classify the material according to the classification of the NF P 11 300 standard and the GTR. Calavi bar soil contains a high proportion of fine particles. It is a sand-clay mixture. Its plasticity index shows that it is a material that can be used in the making of stabilized earth blocks. The Compressed Earth Block (CEB) stabilized with cement and lime at the same percentage, namely 6-8 and 10%, underwent simple compression tests, three-point bending, abrasion and water absorption by capillary action. The comparative study of the results revealed that CEB stabilized with cement are more resistant and less porous than those stabilized with lime.

Highly thermally conductive BNNS/PANF dielectric composite boards prepared by a facile compression moulding process

Highly thermally conductive BNNS/PANF dielectric composite boards prepared by a facile compression moulding process

Active Stratification of Colloidal Mixtures for Asymmetric Multilayers.

Stratified films offer high performance and multifunctionality, yet achieving fully stratified films remains a challenge. The layer-by-layer method, involving the sequential deposition of each layer, has been commonly utilized for stratified film fabrication. However, this approach is time-consuming, labor-intensive, and prone to leaving defects within the film. Alternatively, the self-stratification process exploiting a drying binary colloidal mixture is intensively developed recently, but it relies on strict operating conditions, typically yielding a heterogeneous interlayer. In this study, an active interfacial stratification process for creating completely stratified nanoparticle (NP) films is introduced. The technique leverages NPs with varying interfacial activity at the air-water interface. With the help of depletion pressure, the lateral compression of NP mixtures at the interface induces individual desorption of less interfacial active NPs into the subphase, while more interfacial active NPs remain at the interface. This simple compression leads to nearly perfect stratified NP films with controllability, universality, and scalability. Combined with a solvent annealing process, the active stratification process enables the fabrication of stratified films comprising a polymeric layer atop a NP layer. This work provides insightful implications for designing drug encapsulation and controlled release, as well as manufacturing transparent and flexible electrodes.

Mechanical Compression‐Enabled Carbon‐Based Perovskite Solar Cells with Enhanced Efficiency and Stability

Carbon electrode‐based perovskite solar cells (C‐PSCs) without hole transport layer (HTL) have been emerging as a promising low‐cost photovoltaic technology with excellent stability for commercialization. However, the loose physical contact between the carbon electrode and perovskite layer, as well as the relatively poor conductivity of the carbon film, contributes mainly to the large gap in the power conversion efficiency (PCE) between C‐PSCs and the metal (Ag, Au, etc.,) electrode‐based counterparts. To this end, a simple but effective mechanical compression strategy for efficient C‐PSCs is developed. The mechanical compression densifies the porous carbon electrode for high film conductivity and also provides intimate contact between carbon and perovskite layers for fast charge extraction. Consequently, the resulting HTL‐free C‐PSCs using MAPbI3 (MA = methylammonium) absorber yield a PCE of 15.29%, corresponding to a 27.6% improvement compared to the counterpart without mechanical pressing treatment. Moreover, the compacted carbon film also serves as an enhanced barrier against the intrusion of water and oxygen, and the unencapsulated device retains 88.9% of its initial PCE after 1000 h of aging in ambient conditions with 35 ± 2% humidity. This work paves a simple and effective way toward efficient and stable C‐PSC.

Energy, exergy, environmental (3E) analyses and multi-objective optimization of vortex tube coupled with transcritical refrigeration cycle

Energy, exergy, environmental (3E) analyses and multi-objective optimization of vortex tube coupled with transcritical refrigeration cycle

Incorporation of Liquid WTP Sludge into Compacted Soil–Cement Mixtures

The sludge from water treatment plants (WTP) is a waste from the water process. This study evaluated the effect of incorporating water treatment plant (WTP) sludge, replacing the water used in compacted soil–cement mixtures. The materials were characterized by Scanning Electron Microscopy (SEM) associated with Energy Dispersive Spectroscopy (EDS) and Atomic Absorption Spectrometry (AAS). The soil, with the addition of liquid WTP sludge, presented an apparent dry specific weight (ƴd) of 1.77 gf·cm−3, the optimum moisture value in the compaction test of 15%, and the cement contents tested were 7, 11, and 14%. The specimens were molded using a WTP sludge–cement–soil mixture under the conditions mentioned above, and the simple compression results showed values within the range of 2.5 to 9.3 MPa, as specified by the Brazilian Technical Standard (NBR) 8491/2012. The hydraulic conductivity performed on the test specimen after 28 days of curing resulted in a coefficient (k) of 7.49 × 10−9 cm·s−1, classified as little permeable. The result obtained from aluminum leaching was 0.12 mg·L−1, within the maximum limit allowed by NBR 10004/2004. Therefore, liquid WTP sludge has a significant capacity for incorporation into the compacted soil–cement mixture and the potential to manufacture ecological bricks, an alternative environmentally sustainable brick.

PETROGRAPHIC, MINERALOGICAL AND GEOMECHANICAL CHARACTERIZATION OF SANDSTONES EXPLOITED IN QUARRIES IN KINSHASA

The sandstone of Inkisi, serving as support for infrastructure and construction materials in the city province of Kinshasa, is of interest for geomechanical studies in particular and geological studies in general. Given its outcrop almost everywhere in Kinshasa and its high consumption in the field of buildings and public works, we have set ourselves the main goal of its macroscopic petrographic characterization and on thin sections using a polarizing microscope, mineralogical by X-ray diffraction and geomechanical by Simple and Los Angeles compression tests using quarry samples from the Kimwenza and Kinsuka sandstones. Petrographically, they are essentially arkosic sandstones. X-ray diffraction reveals the abundance of quartz in our sandstones. It also allowed the detection of minerals containing titanium in addition to feldspars. The simple compression test showed that these sandstones follow mode A from the point of view of rupture and that these sandstones belong to the class of medium strength from the point of view of the classification of resistance to simple compression. The Los Angeles test suggests that these sandstones have a coefficient in the good to average range. And therefore, on a geomechanical level, the sandstones studied in the two quarries of Kimwenza and Kinsuka are suitable for various construction works.

Form-stable Na2CO3-NaCl/mullite phase change composite with SiC enhanced thermal conductivity for high temperature thermal storage

Form-stable Na2CO3-NaCl/mullite phase change composite with SiC enhanced thermal conductivity for high temperature thermal storage