bluuebunny/crossref_metadata_2025 huggingface dataset:
FEASIBILITY STUDY OF INDUSTRIAL JAROSITE WASTE AS VITAL MATERIAL FOR CONSTRUCTION: POSITIVE AND NEGATIVE ASPECTS
Authors: Sharma Piyush
Published: July 2024

Jarosite is a basic hydrous sulphate containing potassium and iron. Jarosite is often produced as a by-product during the purification and refining of zinc. The Jarosite mainly contains iron, sulphur, zinc, calcium, lead, cadmium and aluminium. The work presented here will overview the physical and chemical characteristics of Jarosite and as well as the work done by various authors. This paper will study the potential application of Jarosite in various engineering works such as road construction, airfields, dams, bricks and tiles. The text deals with various positive and negative aspects of using Jarosite for engineering purposes as Jarosite released from industrial process is complex and its quality and quantity make the task more complex for safe disposal. Due to the increasing of annual production of Jarosite, it is a major source of pollution for surrounding environment including soil, vegetation and aquatic life.
EFFECT OF COMPACTIVE EFFORTS ON DESICCATION â€“ INDUCED VOLUMETRIC SHRINKAGE STRAIN OF SOME COMPACTED TROPICAL SOILS
Authors: Kundiri Ali Musa , Muhammed Abubakar Sadiq , Abah Gabriel
Published: July 2024

This paper presents an experimental study of the desiccation-induced volumetric shrinkage strain for two compacted soils classified as A (A-6) and B (A-7-6)according to the Association of American States Highway and Transportation Officials (AASHTO) Classification System and CL according to the Unified Soil Classification System (USCS). The samples were prepared using three compactive efforts of Reduced Proctor (RP), Standard Proctor (SP) and Modified Proctor (MP) at moulding water contents relative to optimum (i.e. -2, 0, +2 and +4%). Samples were extruded from the compaction moulds and allowed to air dry in the laboratory in order to assess the variation of desiccation-induced shrinkage on the material with days and its potentials as a hydraulic barrier in waste containment applications. Results showed that soils compacted using the higher compactive effort showed lower values of volumetric shrinkage strain (VSS) due to the closer packing of soil fabric as a result of higher energy. Similarly, VSS increased with higher moulding water content for specimens compacted on the wet side of the optimum and contain much water as against the specimens compacted on the dry side of the optimum which had less water. At 7 and 14 days cured specimens using the RP compactive effort showed similar features, and up to 2% on the dry side of the optimum for 0 and 21 days cured specimens. The SP compactive effort for 7 and 14 days cured specimens yielded the peak dry densities at 2% on the wet side of optimum and at optimum. The MP compactive effort, the samples compacted at 2% on the wet side of optimum and 2% on the dry side of optimum showed similar behaviours for the hydration periods of 0 to 14 days curing period considering soil sample A. For soil sample B, at 14 and 21 as well as 7 and 21 days cured specimens showed highest dry densities with similar features for, 2% on the wet side of optimum up to the optimum; but changes at 2% on the dry side of optimum for both RP and SP compactive efforts respectively. The predicted models measured adequately the estimation of VSS value using the analysis of variance (ANOVA) and gave good indication of validity.
STRUCTURAL BEHAVIOR OF THE HYBRID COMBINATION OF CFRP-BFRP SHEETS IN RETROFITTING OF RC BEAMS BASED ON NONLINEAR FINITE ELEMENT ANALYSIS
Authors: Metwally Ibrahim Mohamed
Published: July 2024

The use of composite materials such as fiber-reinforced polymers in strengthening and repairing of reinforced concrete elements is widely spreading. However, for successful and costeffective applications, engineers must improve their knowledge with respect to the actual behavior of strengthened structures. The CFRP sheets used in strengthening applications have high strength; however, they are brittle materials with low ductility. Basalt fiber reinforced polymer (BFRP) sheets on the other hand have relatively lower strength compared to CFRP, however they have higher ductility and cheaper than carbon fibers. As a result, there is growing interest among researchers and practitioners in combining different types of FRP sheets to produce an enhanced strengthening system in terms of strength and ductility. This hybrid system is designed to enhance the properties of composites, where it combines the high strength of CFRP and high ductility of BFRP sheets, respectively. This paper presents the nonlinear finite element analysis (FEA) that has been carried out to simulate the behavior of failure modes of reinforced concrete (RC) beams strengthened in flexure using CFRP sheets, BFRP sheets, and their hybrid combination (CFRP-BFRP). Besides, new technical approach is presented numerically to show that concrete cover replacement with high strength concrete one provided better load capacity and failure mode, indicating utmost utilize of the hybrid combination of CFRP-BFRP in strengthening of RC beams. The commercial and general finite element analysis; ABAQUS software is used for modeling and nonlinear analysis. Load deflection relationships, failure mode, ductility, ultimate load and ultimate deflection were obtained and compared with the recent experimental results available in literature. From the analysis, it is found that FEA can predict accurately the load-displacement relation and good agreements were obtained when compared to the experimental data. In addition, the proposed FE analysis can be reliably used as a cost-effective tool to predict the inelastic behavior of strengthened beams.
ENGINEERING GEOLOGICAL OF AN ACTIVE SLOPE IN KM46 SIMPANG PULAI, PERAK
Authors: Md Yusoff Zainuddin , Azmi Nur Anati , Nahazanan Haslinda , Nik Daud Nik Norsyahariati , Abd Aziz Azlan
Published: July 2024

Engineering geological mapping is an essential tool to understand the geotechnical threshold values triggering slope failures. The slope chosen is the KM 46 Jalan Simpang PulaiCameron Highlands in Perak. A geological map composed of the confirmed and probable bedrock layer may it be on the ground surface or immediately underneath the soil layer. The soil layer can be transported materials and also can be the residual soil of the bedrock. Engineering geological maps include additional engineering geological information such as dips and strikes of the unconformities, Standard penetration Tests (SPT) values .geormorphological informations and topograhy inputs.
DETERMINATION OF U-SHAPED CONCRETE PANEL FOR LOW BEARING CAPACITY SUBGRADE
Authors: Kamarudin Nur Aiza Shuhada , Mohamed Azman , Md. Nor Hasanan , Ismail Muhammad Rais
Published: July 2024

The concept of using U-shaped Concrete Panel (USCP) is expected to be a solution in strengthening low bearing capacity subgrade, used as foundation for rural road. The objective of this paper is to present the experimental feasibility in designing and testing of the USCP. The USCP has a shape of a panel with webs coupled at both end. The shape is designed to have optimum flexural strength as well as to overcome heaving of the ground. This USCP also should give an interlocking effect to the soil in contact with the USCP. The design of the shape is determined by the concept of U-shaped drain and shear failure of soil. This USCP further give advantage in providing strength to the low bearing capacity subgrade. Experimental tests included to determine the engineering properties of the USCP are the flexural strength test, dropweight impact test, and dynamic load test. In this study, this USCP is aimed to be able to provide additional strength to the subgrade without disturbing the native soil.
COPPER AND ZINC ACCUMULATION IN SEDIMENT AT STRAITS OF JOHOR
Authors: Maadin Farah Syuhada , Abdul Rahman Mohammad Faedzwan , Abdullah Zawawi Mohd Asadi , Azman Shamila , Oladokun Sulaiman
Published: July 2024

A study was carried out to investigate heavy metal level in aquatic environment and its effect due to land use. The main objective of this study is to evaluate the concentration of copper (Cu) and zinc (Zn) in sediment at Straits of Johor. Four sampling stations in Kampung Pasir Puteh were chosen for sediment sampling. Heavy metal analysis was carried out for zinc (Zn) and copper (Cu) using Atomic Absorption Spectrophotometer (AAS). The in-situ results showed dissolved oxygen concentration in the range of 0.31 to 5.90mg/L while pH was recorded at 7.35 to 8.29. Heavy metals analysis in sediment for copper depicts copper accumulation in sediments exceeded the allowable limit at Station 5 whereby the highest readings recorded was 146 Âµg/g. Zinc accumulation at Station 3, Station 4 and Station 5 exceeded the allowable limit which was 271 Âµg/g. Enforcement should be taken to reduce the accumulation of pollutants thus can prevent the aquatic environment from polluted.
CARBONIZED GREEN MUSSEL SHELL AS HEAVY METAL REMOVAL
Authors: A. Rahman Nur Afifah , Mohd Said Mohd Ismid , Azman Shamila
Published: July 2024

Large amount of mollusc shell are usually disposed off and can a create nuisance due to odor and its quantity. Therefore this study aims explored the adsorption capacity of green mussel (Perna viridis) shell for cadmium, chromium and lead from aqueous solutions.. The adsorbent has prepared from powdered green mussel shell in the form of carbonized adsorbents shells at 600Â°C. The carbonization process was conducted for four hours and allowed to cool at room. Characterization of pH, bulk density, moisture content and ash content was also conducted. The effect of various operational parameters such as concentration, pH, temperature and sorption time on the adsorption of heavy metals were investigated using batch process experiments It was found that green mussel shell can be used as a low cost adsorbent for the removal of heavy metals in aqueous solution. The maximum ion adsorption capacities followed the trend lead > chromium > cadmium and the percentage adsorption was found to depend on the concentration of the adsorbent present, the solution pH, temperature and the sorption. This shows that the adsorption of metal ions on the adsorbent is chemisorption. Kinetic treatment of the results gave a pseudo-second order type of mechanism while the adsorption characteristics of the adsorbent followed the Freundlich adsorption isotherm. The results obtained proved that green mussel shells can be alternative resources of adsorbent materials.
RAINFALL RUNOFF PERFORMANCE OF SMALL SCALE GREEN ROOFS SYSTEM
Authors: Kasmin Hartini , Ag Binting Noor Fadzilah , Atan Norbaasithu , Razak Nur Syafira , Yusoff Nor Azizi , Kassim Rosniza , Ahmad Hanim , Sayuti Zulhazmi
Published: July 2024

As green roof technology is still emerging, there is limited rainfall runoff data available at present under Malaysian climate. Located at equatorial region, Malaysia will sometimes experience high humidity and high temperatures throughout the year. Hence this study will present the initial outcomes of the joint initiative between Malaysia Agricultural Research and Development (MARDI) and Universiti Tun Hussein Onn Malaysia (UTHM) in promoting this green roof technology in Malaysia. The study aims to provide initial observation on rainfall runoff performance using the green roofs set up by MARDI. Initially this green roofs system were set up for the agriculture study of three different vegetation and two treatment systems which known as conventional and self-watering system, under two different substrate depths which are 50 mm and 100 mm. Six rainfall events were manually observed consists of one extreme rainfall and five moderate rainfall type. It is found that the highest retention from the event with total rainfall of 94.7 mm was 49.8% for 5SWLC (50 mm substrate depth + self-watering system + Lantana camara) but the retention varied between 38.1% and 47.0% for moderate rainfall range between 30.3 mm and 35.4 mm for the same roof treatment. At the same time, the other treatment systems with other type of vegetation and depths show lesser retention than the 5SWLC. It can be concluded that with the additional storage system, may increase the typical total retention for green roofs.
PAVEMENT STRUCTURAL ASSESSMENT USING AUTOMATED TOOLS: A COMPARATIVE STUDY
Authors: Muslim Nurul Hidayah , Mohamed Mohamad Ibrahim , Mat Amin Zulkarnaini , Shafaghat Arezou , Ismail Mohammad , Keyvanfar Ali
Published: July 2024

Pavement distress evaluation was traditionally conducted through visual observation. Traditional practice requires a person to walk along the stretch of pavement in order to survey distresses, take photos, and measure defects occurred at the deteriorated surface. However, this approach is too subjective causes inconsistencies of information, less reliable and time-consuming. Due to these shortcomings, the practitioners in pavement maintenance sector seek for a reliable alternative tools and techniques to arrest incapability of traditional approach. This research aimed to investigate feasibility of automated tools for pavement structural assessment conducting a comparative study. Series of interviews with expert panels and comparison matrix have been conducted comparing Ground Penetrating Radar (GPR), Infrared Thermograph (IR), and Portable Seismic Pavement Analyzer (PSPA) by investigating across parameters; cost-time effectiveness, operating principle, depth of performance, method of application, and limitations of pavement evaluations. The research indicated the Ground Penetrating Radar (GPR) is highly advantageous over IR and PSPA for pavement structural assessment. The GPR, as a geophysical tool, has extensive capabilities to accommodate data in pavement assessment, geotechnical investigation and structural assessment. GPR can considerably perform at high speed and save time. It is also beneficial for long-term investment with deeper information. Notably, the interpretation of radar gram images of GPR tool needs sufficient time and skill.
SCALE EFFECT ON THE SHEAR STRENGTH OF TWO-LAYER SOIL REINFORCED BY GEOGRID
Authors: Tamassoki Sakine , Z. Moayed Reza , Ashkani Mohammad , Rahimi Hamidreza
Published: July 2024

Geosynthetics are used to reinforce soils and improve their mechanical characteristics,especially when soft low-bearing capacity soils are encountered in civil engineering projects.Particularly, in roads, geosynthetics are placed between the interface of granular materials andsoft-soil sub grade to improve composite layersâ€™ bearing capacity. This paper presents the resultsof the finite element analysis of the two-layer soil(granular base-clayey sub grade) reinforced bygeogrid and discusses the effect of the reinforcement on the shear strength. As the primary aim ofthe study, the numerical model was calibrated in comparison with the experimental results oflarge scale direct shear tests. The results showed that the shear strength improved in the two-layersoil which had been reinforced by geogrid. The predictions made by the developed model werefound to be in line with the experimental data obtained from large scale direct shear tests. Asanother aim of the study, different dimensions of shear box were used for modelling in order toinvestigate the scale effect on the shear strength of double-layered soil (clay-sand). The resultsshowed that the increase in the dimensions of the reinforced shear box leads to the enhancementof peak shear strength. Moreover, several analyses were conducted on geogrid in shear box withdifferent dimensions in fixed and unfixed states. The results demonstrated that the shear strengthof treated geogrid was higher than the shear strength of those in which untreated geogrid wasutilized.
COMPARATIVE ANALYSIS ON CONSTRUCTION ADJUDICATION SYSTEMS TOWARDS EFFECTIVE IMPLEMENTATION OF STATUTORY ADJUDICATION IN MALAYSIA
Authors: Mohamed Nasir Nur Ilylia Iryani , Ismail Zulhabri , Muhd Fadhlullah Ng Nur Khodijah
Published: July 2024

The dynamic nature of the construction industry makes it almost impossible to maintain a project without any disputes. Of all the addressed disputes in the construction industry, payment disputes are seen to be the most critical issue to be apprehended; as there is no doubt that consistent cashflow is important to distinguish the projectâ€™s development and achievements. Adjudication is one of the remedies to assist in arresting these problems, and the way to make an impact to the implementation of adjudication is by having it an enforceable statute. Along the years, fourteen adjudication Acts have been introduced within the Commonwealth countries. As the Construction Industry Payment and Adjudication Act 2012 is a hybrid of few adjudication systems in the world, a comparative study on three adjudication Acts: the Housing Grants, Construction and Regeneration Act 1996 of the UK â€“ the first statutory adjudication implemented, Building and Construction Industry Security of Payment Act 1999 of Australia â€“ consists of a unique set of judicial systems that needs to be considered separately and Building and Construction Industry Security of Payment Act 2004 of Singapore â€“ one of the latest implemented statutory adjudication before CIPAA; were looked into, and possible matters affecting their effective implementation were emphasized. This review aims to assist in identifying the possible issues that might be faced by the Construction Industry Payment and Adjudication Act 2012 (CIPAA) as a newly legislated Act in Malaysia and possible corrective measures that could be undertaken to enhance its effectiveness.
A QUALITATIVE PERFORMANCE ANALYSIS OF ROTARY INTERSECTIONS IN AN URBAN METROPOLIS, NIGERIA
Authors: Yusuf Ibrahim Tunde , Andy Abur Aondoaseer , Ako Terseer , Bilewu Solomon Olakunle
Published: July 2024

Assessment of the qualitative performance of a roundabout in relation to factors, such as delays, queues, level of service (LOS), accident, operation cost and environmental issues is necessary for its successful operation. This study, therefore, aims at analysing the qualitative performance of roundabouts in an urban area, Nigeria with the Fate roundabout in Ilorin metropolitan city as study case. The movement of the vehicles was observed and traffic counts carried out manually, at 15 minutes intervals for 12 hours (6:30am-6:30pm) daily for seven (7) days, from Monday, June 15th to Sunday, June 21st, 2015. Results show that, the five (5) working days (Monday-Friday), have high traffic volume counts and were selected for the analysis. Peak hour factors (PHF) were used to convert the demand volumes to flow rates. The qualitative performance analyses were carried out based on the 12-step approach for the performance analysis of a roundabout as outlined by the Highway Capacity Manual. Approach and entry capacities were determined as mathematical functions of critical headway, and follow-up headway were then estimated using the analytical approach. The degree of saturation, delay, and queue length used in estimating the performance of a roundabout were also determined. The relation between the roundabout performance measure and capacity, expressed in terms of degree of saturation shows that the performance of the Fate roundabout ranged between LOS A â€“ E. An increase in the entry lane width at Basin road approach was recommended to ensure continuous and smooth flow at the roundabout.
FLEXURAL CAPACITY ASSESSMENT OF BRICK AGGREGATED PRE-CRACKED RC BEAM STRENGTHENED WITH CARBON FIBER POLYMER
Authors: Mamun Niaz Md , Islam G. M. Sadiqul , Alam Md Jahangir
Published: July 2024

Ageing and improvements to design code has led to many existing RC structures made of locally available brick aggregates are now found structurally deficient and are in need of rehabilitation. This research emphases on flexural capacity assessment and investigation of failure modes of Carbon Fiber Reinforced Polymers (CFRP) strengthened brick aggregated RC beams. Flexural performance of the RC beam specimens are evaluated using four point bending method. Six RC beams (initially cracked) with CFRP strengthening were tested by varying (i) type of CFRP, (ii) reinforcing area, (iii) anchorage type; and (iv) number of CFRP layers. Two beams were tested as control specimens. Unidirectional carbon fiber sheet (Tow Sheet) and individually hardened continuous fiber strands woven into sheet form (Strand Sheet) were used. Simple flexure failure was obtained for unstrengthened RC beams while end plate and interfacial debonding were observed for the initially cracked CFRP strengthened RC beams. Strengthening of pre-cracked beams using Strand Sheet gave better performance compared to Tow sheet. Overall flexural strength improvement of CFRP strengthened beams varied from 12% to 34% with respect to unstrengthened beams depending on strengthening methods.
COMPOSED COEFFICIENT TECHNIQUE FOR MODELLING BARRETTE GROUPS
Authors: El Gendy Mahmoud , Ibrahim Hassan , El Arabi Ibrahim
Published: July 2024

Most of soil structure interaction methods for analyzing large-section supports such as barrette foundation modeling and the surrounding soil are using 3D finite element (FE) models. In which, the model leads to a large finite element mesh, and consequently a large system of linear equations to be solved. In this paper, Composed Coefficient Technique (CCT) is adapted for analyzing barrette group. The technique considers the 3D full interactions between barrettes and the surrounding soil. Due to the high rigidity of the barrettes relative to the surrounding soil, a uniform settlement for the barrettes can be considered. This is done to compose the stiffness coefficients of the soil matrix into composed coefficients, which consequently leads to a significant reduction in the soil stiffness matrix. An application for analyzing barrette group by CCT technique is carried out on a real subsoil. The application presents guidelines and diagrams for barrette group that may be used in real practice.
BOND AND FLEXURAL STRENGTH CHARACTERISTICS OF PARTIALLY REPLACED SELF-COMPACTING PALM KERNEL SHELL CONCRETE
Authors: Odeyemi Samson Olalekan , Abdulwahab Rasheed , Abdulsalam Adebayo Akeem , Anifowose Mukaila Abiola
Published: July 2024

Self-compacting concrete (SCC) is an innovative concrete that has helped in overcoming challenges associated with vibrated concrete such as congested reinforcements, noise from vibrators, and cost of hiring vibrators. This research examined the bond strength between partially replaced Self Compacting Palm Kernel Shell (SCPKS) concrete and high yield reinforcing bars wherein the granite content of the concrete was replaced by 50% of palm kernel shell (total replacement disintegrated on removal of mould). SCPKS concrete specimens of mix ratios 1:2:4, 1:1.5:3 and 1:1:2 were produced and cured for 7 days, 21 days and 28 days at water to cement ratio (w/c) of 0.5 and 0.6 respectively. Flow, bond strength, and flexural tests were conducted on the samples. The highest bond strength was recorded for mix ratio 1:1:2 at w/c of 0.5 when tested at 28 days with a value of 5.56 N/mm2. This value is 0.072% higher than the 28th day strength of 5.52 N/mm2 for SCC without replacement of the granite content. Also, the highest flexural strength was recorded for mix ratio 1:1:2 at w/c of 0.5 when tested at 28 days with a value of 6.88 N/mm2. It was concluded that palm kernel shell can be safely used for partial replacement in SCC.
COMPRESSIBLITY OF PEAT SOIL IMPROVED WITH POLYURETHANE
Authors: Mohamed Jais Ismacahyadi Bagus , Che Lat Diana , Tengku Endut Tengku Nur Dalila
Published: July 2024

This research investigated the compressibility of natural peat soil and peat soil improved with polyurethane foam. High natural moisture content, high compressibility, low bearing capacity and medium to low permeability is a problem and characteristic of a peat soil. This problem can be solved by reducing the compressibility of the peat soil. The objective of this study is mainly to prove whether the presence of polyurethane foam as a lightweight material on peat soil can reduce the compressibility of peat soil or otherwise. Fifteen samples of peat soil taken from Johan Setia, Klang were tested using Oedometer test with load is doubled at each increment until it reaches the maximum required load which is 10kPa, 20kPa, 40kPa, 80kPa, 160kPa, 320kPa and 640kPa. Polyurethane foam is a lightweight material, therefore reduces the overburden pressure to the underlying soil, hence future settlement can be minimized to a tolerable settlement value. Based on the data obtained from analysis of Oedometer test, the compressibility parameters including void ratio, compression index and swelling index of the peat soil alone are very high which denoted extremely poor condition of the peat soil. The compressibility parameters improved significantly with the PU foam stabilization as PU act as a void filler for peat soil. A slight increase in the compressibility parameters are recorded with higher ratio of isocyanate.Â  However, the maximum pre-consolidation pressure recorded was with PU ratio of 1:1. Therefore, the optimum ratio for PU peat stabilization is in the ratio of 1:1.
ENHANCED MESHFREE RPIM WITH NURBS BASIS FUNCTION FOR ANALYSIS OF IRREGULAR BOUNDARY DOMAIN
Authors: Mokhtaram M.H. , Mohd Noor M.A. , Jamil Abd Nazir M.Z. , Zainal Abidin A.R. , Mohd Yassin A.Y.
Published: July 2024

Radial Point Interpolation Method (RPIM) has become a powerful tool to numerical analysis due to its ability to provide a higher-order approximation function with the Kronecker delta property, by which the field nodes can be fitted exactly. However, one of the major drawbacks of RPIM is the inefficiency in handling irregular domain problems. This paper presents an enhanced RPIM formulation that employs Non-Uniform Rational B-Splines (NURBS) basis functions to represent the exact geometry of the boundary domain. The NURBS is a mathematical model which provides an efficient and numerically stable algorithm to exactly represent all conic sections in engineering modelling. Taking advantage of the flexibility and adaptivity of RPIM approximation and the accuracy of geometric representations by NURBS, this new method is able to improve geometry accuracy and flexibility in numerical analysis, thus providing a better and more rational approach to analyze irregular domain problems. Numerical problem of steady heat transfer considering curved beam is presented to verify the validity and accuracy of the developed method. The essential boundary condition can simply be imposed using direct imposition as in Finite Element Method (FEM). The result shows that the RPIM/NURBS achieved the converged solution much faster than conventional RPIM and FEM, with the number of nodes required only less than 200 for an error of less than 0.01%. This shows the potential of the developed method as a powerful numerical technique for future development.
MODELING AND EVALUATION OF THE STRENGTH PROPERTIES OF OKE-BALE SOFT SOIL AMENDED WITH CALCIUM CHLORIDE SALT
Authors: K. Ishola, , K.A. Adeyemo, , M.A. Kareem, , M.Y. Olawuyi,
Published: July 2024

This research aimed to model and assess the impact of calcium chloride salt (CCS) on the Oke Bale soft soil, known as Lateritic soil, in Osogbo, Nigeria, as a potential pavement material due to high cost of conventional materials. The conducted laboratory tests included particle size distribution, Liquid limit (LL), Plastic limit (PI), and Plasticity index (PI), compaction (Maximum dry density (MDD); Optimum moisture content (OMC) with compactive efforts of British Standard Light, West Africa Standard, and British Standard heavy, and unsoaked California bearing ratio (CBR) on both Oke bale soft soil and modified soil. The soft soil underwent stabilization with varying concentrations of CCS at 0, 4, 8, 12, and 16%. The results were analyzed using regression analysis and Analysis of Variance (ANOVA). The findings indicated advancement in the gradation of lateritic soil as the percentage of CCS salt increased. Additionally, the PI lessened from the value of 14.68% in the regular lateritic soil to the value of 11.49% at 12% CCS content, afterward amplified to the value of 15.6% at 16% CCS content. Simultaneously, the LL of the natural lateritic soil decreased from 60.05% to 35.55% at 16% CCS content. The MDD of original lateritic soil for BSL, WAS, and BSH decreased from 1.63 to 1.45 Mg/dm³, 1.66 to 1.48 Mg/dm³, and 1.69 to 1.52 Mg/dm³ at 4% CCS content, subsequently increasing up to 16% CCS, respectively. Although the OMC amplified from 19.47% to 24.0%, 18.22% to 22.73%, and 17.44% to 21.85% at 4%, it later increased up to 16% CCS, respectively. At 8% CCS content, the CBR value improved from 13.22% to 24.65%, 14.44% to 26.28%, and 15.68% to 28.62% for BSL, WAS, and BSH compactive effort, respectively. Regression analysis indicated that grading properties, MDD, LL, PF, and PI influenced strength qualities of Oke-bale lateritic soil amended with CCS, with positive coefficient values. Furthermore, regression analysis suggested a solid bond between the measured and predicted values of CCS-LS. However, statistical significance was shown in the lateritic-CCS mixed analyses of variance during the duration of the test. Based on the outcome of CBR test, 8% CCS-lateritic soil mixture could be effectively utilized to enhance low-traffic roads.
EVALUATING THE STRUCTURAL EFFICACY OF ANGLE AND CHANNEL SHEAR CONNECTORS IN BRICK AGGREGATE CONCRETE AND STONE AGGREGATE CONCRETE AND COMPARISON
Authors: Akram Mostafa Humayun , Alam Md. Rabiul , Haque Md. Naimul , Hossain Md. Tanzim
Published: July 2024

Composite structure is becoming prominent for its economy, less time consumption, and higher stiffness-mass ratio. Composite action of the steel-concrete composite structure mainly depends on the connector's geometry and materials. Proper choice of shear connector could make steel beam and concrete slab cross-section minimal. This study carries out push-out tests to evaluate the structural efficiency of channel and angle shear connectors in brick aggregate concrete and stone aggregate concrete. It specifically looks at the failure mode, ductility, load-slip behavior, and energy absorption capacity. In brick aggregate concrete, results show that under monotonic loading, channel connectors have been found to have 15.27% more shear capacity & 28.38% more slip than angle connectors. Similarly, in stone aggregate concrete, channel connectors have been found to have 14% more shear capacity & 12.97% higher slip than angle connectors. On average, stone aggregate concrete has been found to have 34.84% higher shear capacity and 6.7% greater slip than brick aggregate concrete. Strain energy and plastic energy were found 78% and 17.6% less in brick aggregate specimens than those in stone aggregate specimens, respectively. Experimental results were slightly lower for both shear connectors than the empirical values.
COMPRESSIVE STRENGTH PREDICTION FOR SELF-COMPACTING CONCRETE USING ARTIFICIAL NEURAL NETWORKS
Authors: Odeyemi Samson Olalekan , Akinwamide Joshua Tunbosun , Olawale Mokanmiyo Adedeji , Akinwamide Oluwayinka Glory , Wilson Uwemedimo Nyong
Published: July 2024

This study investigates the relationship between concrete constituent materials, slump values, density, strain and compressive strength. The database was set in the laboratory by performing a quality assurance test on the constituent materials to ascertain their suitability for concrete work.  For material procurement and selection, the British Standard Department of Environment DOE technique of concrete trial mix designs was used. In this study, twelve concrete mixes were utilized. Two simplified models were developed using the feedback network Artificial Neural Networks architecture (ANNs) with R version 4.0.5 and R studio version 1.2.5033. In the two models, an independent layer comprising six nodes and a dependent layer comprising two nodes were taken. Having carried out the sensitivity analysis, the capacity of the developed equation was evaluated in terms of error metrics MSE and RMSE. The grading envelope for river sand showed that the graph fell perfectly into grading envelope zone 2 while other constituent materials tested were all confirmed suitable for concrete works. The results of compressive strength were obtained from varied water-cement ratios used for the concrete trial mix design which ranges between 0.45 to 0.6. The compressive strength results showed that the results increased consistently for each design mix. It is worthy of note that the strength of the mix fell between grades 15, 20, 25 and 35 respectively for both the 7-day and 28-day strength accordingly. Conversely, the ANN models predicted both 7-day and 28-day strength close to the laboratory value. It is concluded that this research has demonstrated economic viability which would enhance overall construction planning efficiency for future researchers, consultants and contractors in the building industries.
Acts of Providence: The religious latency surrounding and shaping Marbury v. Madison and the Status-Denkschrift
Authors: Spindola Diniz Ricardo
Published: July 2024

Franklin D. Roosevelt recommended that “like the Bible, [the Constitution] ought to be read again and again.” Gustav Heinemann portrayed the Grundgesetz as a “great offering,” whose words must become flesh. Nevertheless, does this have any bearing on constitutional adjudication? Although presidents didn’t – and more and more don’t – shy about handling their respective constitutions as bibles, have justices and constitutional scholars proceeded otherwise? Common wisdom may answer yes, they did. The aim of my study is to show that this not quite the case. I pursue it in reference to two, leading liberal democratic constitutional courts, the US Supreme Court and the German Federal Constitutional Court. This happens in three parts: (1) I will engage with court architecture, understood as a testimony to each institution’s articulation for self-justification and self-empowerment; (2) the semantic consecration of constitutional adjudication especially vis-à-vis politics, as it took place in the struggles over what was implied by the innovations pushed forward in the contexts of Marbury v. Madison, on the one hand, and of the German Constitutional Court’s Status-Denkschrift, on the other; (3) and legal-methodological debates on the relationship between the Christian Bible and constitutional provisions that run in parallel and connection to these two landmark events. My findings point out that, in face of how disruptive the differentiation between law and politics was and is, constitutional actors in 19th century United States and 20th century Germany frequently, if not invariably, relied upon religious resources to embed their positions.
Multistep and Elastically Stable Mechanical Metamaterials
Authors: Wang Lianchao , Iglesias Martínez Julio A. , Dudek Krzysztof K. , Ulliac Gwenn , Niu Xinrui , Zou Yajun , Wang Bing , Laude Vincent , Kadic Muamer
Published: July 2024

Materials and structures with tunable mechanical properties are essential for numerous applications. However, constructing such structures poses a great challenge since it is normally very complicated to change the properties of a material after its fabrication, particularly in pure force fields. Herein, we propose a multistep and elastically stable 3D mechanical metamaterial having simultaneously tunable effective Young's modulus and auxeticity controlled by the applied compressive strain. Metamaterial samples are fabricated by 3D printing at the centimetric scale, with selective laser sintering, and at the micrometric scale, with two-photon lithography. Experimental results indicate an elementary auxeticity for small compressive strains but superior auxeticity for large strains. Significantly, the effective Young's modulus follows a parallel trend, becoming larger with increasing compressive strain. A theoretical model explains the variations of the elastic constants of the proposed metamaterials as a function of geometry parameters and provides a basic explanation for the appearance of the multistep behavior. Furthermore, simulation results demonstrate that the proposed metamaterial has the potential for designing metamaterials exhibiting tunable phononic band gaps. The design of reusable elastically stable multistep metamaterials, with tunable mechanical performances supporting large compression, is made possible thanks to their delocalized deformation mode.
Physics-Informed Sampling Scheme for Efficient Well Placement Optimization
Authors: Kim Jongwook , Kim Dogyun , Jo Woosueng , Kim Joonyi , Jo Honggeun , Choe Jonggeun
Published: July 2024

Well placement optimization is a crucial task in terms of oil and gas recovery and economics in the field development plan. It poses significant challenges due to the multitude of local optima, which demand massive computational cost for global search algorithms. To address this, many proxy models have been applied for replacing reservoir simulations in many cases. Among these, convolutional neural network-based proxy models utilizing streamline time of flight maps as input demonstrated excellent performances. Nevertheless, these models exhibit diminishing performances during optimization processes, so additional retraining processes are required for successful results. In this study, we propose an initial sampling scheme using physics-informed quality maps incorporating static and dynamic information. The quality maps combine drainage area with permeability to represent the quality of each reservoir grid. The proposed scheme provides better performance than other sampling schemes. We demonstrate that the proposed scheme provides efficient well placement optimization regardless of the number of samples without retraining.
Maximizing Waste-to-Energy Potential: Optimizing Batch Torrefaction Reactor of Refuse-Derived Fuel for Efficient Gasification
Authors: Rashwan Sherif S. , Boulet Micael , Moreau Stephane
Published: July 2024

Refuse-derived fuel (RDF) from municipal solid waste is a promising alternative to fossil fuels, but its varied composition can impede direct gasification. This industrial research project conducted a series of batch experiments to assess four key parameters: energy yield, mass yield, energy density, and combustion characteristics in the context of RDF torrefaction. The batch reactor processed RDF samples at temperatures of 250 °C, 300 °C, and 350 °C, each with a 30-minute residence time under an inert atmosphere. In addition, combustion thermogravimetric analysis experiments, involving heating torrefied RDF up to 1000 °C at a rate of 20 °C/min, provided further insights into the robust combustion properties of the torrefied material. Unlocking the secrets of torrefaction magic, we've achieved remarkable energy content boosts. Torrefaction at 250 °C, 300 °C, and 350 °C led to energy content enhancements of 22%, 29%, and 37%, respectively, compared to the original RDF. Notably, the most favorable energy yield was achieved during torrefaction at 250 °C, attributed to both its relatively high energy content and mass yield. At a torrefaction temperature of 250 °C and above, the torrefied RDF samples exhibited heating values comparable to standard coal ranges between 25 MJ/kg and 35 MJ/kg. It is suggested that torrefaction of RDF is an effective pre-treatment process to be used in entrained flow gasifier due to the improved higher heating value, higher energy density, and superior combustion characteristics, proved by the ignition index, flammability index, and burnout index, highlight the effectiveness of the torrefaction process.
Four new species of chiggers (Acariformes: Parasitengonina: Trombiculidae and Leeuwenhoekiidae) and new locality of Quadraseta brasiliensis Goff & Gettinger, 1989 from Brazil
Authors: Pereira Quaresma Leonardo , Pepato Almir Rogério , Gomes-Almeida Brenda
Published: July 2024

Four new chigger species, belonging to genera Leeuwenhoekia Oudemans, 1911 (Leeuwenhoekiidae), Colicus Brennan 1970, and Herpetacarus (Vercammen-Grandjean 1960) (Trombiculidae), are described, based on specimens deposited in the Acarological collection at Centro de Coleções Taxonômicas da UFMG, including voucher material for which sequences from multiple genes are available, sampled from Minas Gerais and Amazonas states, Brazil. Leeuwenhoekia berthalutzae sp. nov. was found in association with the rodent Calomys sp. and Oligoryzomys sp., Colicus helenagrecae sp. nov. with the rodent Cerradomys cf. subflavus, Colicus carolinae sp. nov. in cave soil, off-host, and Herpetacarus mariellae sp. nov. in leaf litter, off-host. Additionally, we report a new record for Quadraseta brasiliensis Goff & Gettinger, 1989 associated with rodents from Parque Nacional Serra do Itajaí, Santa Catarina state.
Adaptation to Change: A Case Study of a Sailor Who Experienced Multiple Career-Change Events and Became a World Champion
Authors: Samuel Roy David
Published: July 2024

This case study describes the adaptation process of a female sailor experiencing several career-change events and transitions. Qualitative data were collected longitudinally as part of a sport psychology consultation process. Data analysis was guided by the meta-model of adaption in sport. Along two Olympic cycles (i.e., Tokyo 2020 and Paris 2024), the athlete experienced multiple changes. These included two transitions between sailing classes, teaming up with a partner, long training camps, an injury, the coronavirus pandemic, and competing in major championships. Transition demands included building team cohesion and developing self-efficacy and mental strength. The athlete exhibited successful and poor adaptation. The applied work facilitating her successful adaptation is presented. Her adaptation ability developed as she progressed in her career, en route to becoming a world champion. These findings provided initial applied-practice support for the meta-model of adaption in sport.
Structural insights into activation mechanisms on NADase of the bacterial DSR2 anti-phage defense system
Authors: Zhang Hong , Li Yu , Li Lanlan , Chen Lifei , Zhu Chunhua , Sun Lifang , Dong Panpan , Jing Dingding , Yang Jinbo , Fu Lei , Xiao Fangnan , Xia Ningshao , Li Shaowei , Zheng Qingbing , Wu Yunkun
Published: July 2024

As a sirtuin (SIR2) family protein, defense-associated sirtuin2 (DSR2) has been demonstrated to participate in bacterial anti-phage resistance via depleting nicotinamide adenine dinucleotide (NAD
+
) of infected cells, which can be activated by tail tube protein (TTP) and inhibited by DSR anti-defense 1 (DSAD1) of diverse phages. However, the regulating mechanism remains elusive. Here, we determined the cryo–electron microscopy structure of apo DSR2, as well as the respective complex structures with TTP and DSAD1. Structural analyses and biochemical studies reveal that DSR2 forms a tetramer with a SIR2 central core and two distinct conformations. Monomeric TTP preferentially binds to the closed conformation of DSR2, inducing conformational distortions on SIR2 tetramer assembly to activate its NADase activity. DSAD1 combines with the open conformation of DSR2, directly or allosterically inhibiting TTP activation on DSR2 NAD
+
hydrolysis. Our findings decipher the detailed molecule mechanisms for DSR2 NADase activity regulation and lay a foundation for in-depth understanding of the DSR2 anti-phage defense system.
Superconducting diode effect under time-reversal symmetry
Authors: Liu Fengshuo , Itahashi Yuki M. , Aoki Shunta , Dong Yu , Wang Ziqian , Ogawa Naoki , Ideue Toshiya , Iwasa Yoshihiro
Published: July 2024

In noncentrosymmetric superconductors, superconducting and normal conductions can interchange on the basis of the current flow direction. This effect is termed a superconducting diode effect (SDE), which is a focal point of recent research. The broken inversion and time-reversal symmetry is believed to be the requirements of SDE, but their intrinsic role has remained elusive. Here, we report strain-controlled SDEs in a layered trigonal superconductor, PbTaSe
2
. The SDE was found exclusively in a strained device with its absence in an unstrained device despite that it is allowed in unstrained trigonal structure. Moreover, the zero-field or magnetic field-even (magnetic field-odd) SDE is observed when the strain and current are along armchair (zigzag) direction The results unambiguously demonstrate the intrinsic SDE under time-reversal symmetry and the critical role of strain-induced electric polarization.
A prM mutation that attenuates dengue virus replication in human cells enhances midgut infection in mosquitoes
Authors: Choi Allyson N. X. , Siriphanitchakorn Tanamas , Choy Milly M. , Ooi Justin S. G. , Manuel Menchie , Tan Hwee Cheng , Lin Lowell Z. , Yap Xin , Gubler Duane J. , Ooi Eng Eong
Published: July 2024

Dengue viruses (DENVs), like all viruses, evolve to perpetuate transmission of their species in their hosts. However, how DENV genetics influences dengue disease outbreaks remains poorly understood. Here, we examined isolates of the South Pacific dengue virus type 2 (DENV-2) that emerged in the 1970s and caused major dengue outbreaks in islands in this region until it reached Tonga, where only a few mild cases were reported. Phylogenetically, the DENV-2 strain isolated in Tonga segregated into a clade different from those clades infecting populations in other South Pacific islands. We found that this epidemiological observation could be explained by a single histidine-to-arginine substitution in position 86 of the premembrane (prM) protein of the Tonga DENV-2 strain. This mutation attenuated viral protein translation in mammalian cells but not in midgut cells of the mosquito vector
Aedes aegypti
. In mammalian cells, the prM mutation resulted in reduced translation of the viral genome and subsequent reduced virus replication. In contrast, in mosquito midgut cells, the prM mutation conferred a selective infection advantage, possibly because of the positively charged arginine residue introduced by the mutation. These findings provide molecular insights into the year-long silent transmission of attenuated DENV-2 in Tonga during the 1970s dengue outbreak in the South Pacific.
A comparative immunological assessment of multiple clinical-stage adjuvants for the R21 malaria vaccine in nonhuman primates
Authors: Arunachalam Prabhu S. , Ha NaYoung , Dennison S. Moses , Spreng Rachel L. , Seaton Kelly E. , Xiao Peng , Feng Yupeng , Zarnitsyna Veronika I. , Kazmin Dmitri , Hu Mengyun , Santagata Jordan M. , Xie Xia , Rogers Kenneth , Shirreff Lisa M. , Chottin Claire , Spencer Alexandra J. , Dutta Sheetij , Prieto Katherine , Julien Jean-Philippe , Tomai Mark , Fox Christopher B. , Villinger Francois , Hill Adrian V. S. , Tomaras Georgia D. , Pulendran Bali
Published: July 2024

Authorization of the Matrix-M (MM)–adjuvanted R21 vaccine by three countries and its subsequent endorsement by the World Health Organization for malaria prevention in children are a milestone in the fight against malaria. Yet, our understanding of the innate and adaptive immune responses elicited by this vaccine remains limited. Here, we compared three clinically relevant adjuvants [3M-052 + aluminum hydroxide (Alum) (3M), a TLR7/8 agonist formulated in Alum; GLA-LSQ, a TLR4 agonist formulated in liposomes with QS-21; and MM, the now-approved adjuvant for R21] for their capacity to induce durable immune responses to R21 in macaques. R21 adjuvanted with 3M on a 0, 8, and 23–week schedule elicited anti-circumsporozoite antibody responses comparable in magnitude to the R21/MM vaccine administered using a 0-4-8–week regimen and persisted up to 72 weeks with a half-life of 337 days. A booster dose at 72 weeks induced a recall response similar to the R21/MM vaccination. In contrast, R21/GLA-LSQ immunization induced a lower, short-lived response at the dose used. Consistent with the durable serum antibody responses, MM and 3M induced long-lived plasma cells in the bone marrow and other tissues, including the spleen. Furthermore, whereas 3M stimulated potent and persistent antiviral transcriptional and cytokine signatures after primary and booster immunizations, MM induced enhanced expression of interferon- and T
H
2-related signatures more highly after the booster vaccination. Collectively, these findings provide a resource on the immune responses of three clinically relevant adjuvants with R21 and highlight the promise of 3M as another adjuvant for malarial vaccines.