An Assessment of the Groundwater Potential of Bayero University Kano Permanent Site Using Induced Polarization and Self-potential Methods

This paper centers on the investigation of the subsurface condition of Bayero University Kano Permanent Site with the aim of understanding the lithology and also mapping out the groundwater patterns within the area. To achieve this, time domain IP （induced polarization） and SP （self-potential） methods were adopted using VES （vertical electrical sounding） technique with 49 stations sounded. The result of the interpreted and analyzed measured data shows that the area is underlain by two to five subsurface layers. These layers are top soil, laterite, weathered basement complex rocks, fractured basement complex rocks and fresh basement complex rocks. The aquiferous zone of the study area occurs in the weathered and fractured basements and its thickness ranges from 1.44 m to 70.157 m while the overburden thickness lies between 1.6 m and 72.104 m. SP values were plotted against depths of investigation in order to identify areas with greater depth of flow in the study area. From the analysis of the overburden thickness, aquifer thickness and SP values, the most favorable regions for groundwater exploitation were found around VES 6, 11, 13, 19, 26, 38, 44 and 48. The investigation also provides information about the subsurface condition with regards to engineering construction and safe place for refuse dumping in order to avoid groundwater contamination.

CRX-527 as a candidate adjuvant in a recombinant BCG-based malaria vaccine

Objective:To investigate the role of CRX-527,a Toll-like receptor 4 agonist,as the possible adjuvant for recombinant Mycobacterium bovis Bacillus Calmette-Guerin expressing merozoite surface protein 1C(BCG-MSP-1C).Methods:The mice were immunized with BCG and BCG-MSP-1C in the presence and absence of CRX-527.The untreated mice(injected with PBS-T80 only)were the negative control.The ability of CRX-527 to enhance IgG and its subclasses,as well as IL-4 and IFN-γproduction in the serum and spleen supernatant was evaluated using ELISA.Results:Mice immunized with BCG-MSP-1C exhibited the highest production of IgGs,IL-4 and IFN-γafter third immunization.In addition,CRX-527 further promoted the production of total IgG and IgG subclasses as well as IFN-γand IL-4 in the serum and splenocytes of immunized mice.Conclusions:CRX-527 has the potential as an adjuvant candidate for the candidate vaccines.Further study is needed to verify appropriate dosage for immunization and its efficacy.

Analysis of CH_(4) and H_(2) Adsorption on Heterogeneous Shale Surfaces Using aMolecular Dynamics Approach

Determining the adsorption of shale gas on complex surfaces remains a challenge in molecular simulation studies.Difficulties essentially stem from the need to create a realistic shale structure model in terms of mineral heterogeneityand multiplicity.Moreover,precise characterization of the competitive adsorption of hydrogen andmethane in shale generally requires the experimental determination of the related adsorptive capacity.In thisstudy,the adsorption of adsorbates,methane(CH_(4)),and hydrogen(H_(2))on heterogeneous shale surface modelsof Kaolinite,Orthoclase,Muscovite,Mica,C_(60),and Butane has been simulated in the frame of a moleculardynamic’s numerical technique.The results show that these behaviors are influenced by pressure and potentialenergy.On increasing the pressure from 500 to 2000 psi,the sorption effect for CH_(4)significantly increasesbut shows a decline at a certain stage(if compared to H_(2)).The research findings also indicate that raw shalehas a higher capacity to adsorb CH_(4)compared to hydrogen.However,in shale,this difference is negligible.

Frequency combs based on magnon-skyrmion interaction in magnetic nanotubes

Within the magnonics community,there has been a lot of interests in the magnon–skyrmion interaction.Magnons and skyrmions are two intriguing phenomena in condensed matter physics,and magnetic nanotubes have emerged as a suitable platform to study their complex interactions.We show that magnon frequency combs can be induced in magnetic nanotubes by three-wave mixing between the propagating magnons and skyrmion.This study enriches our fundamental comprehension of magnon–skyrmion interactions and holds promise for developing innovative spintronic devices and applications.This frequency comb tunability and unique spectral features offer a rich platform for exploring novel avenues in magnetic nanotechnology.

Skyrmion motion induced by spin-waves on magnetic nanotubes

We investigate the skyrmion motion driven by spin waves on magnetic nanotubes through micromagnetic simulations.Our key results include demonstrating the stability and enhanced mobility of skyrmions on the edgeless nanotube geometry,which prevents destruction at boundaries—a common issue in planar geometries.We explore the influence of the damping coefficient,amplitude,and frequency of microwaves on skyrmion dynamics,revealing a non-uniform velocity profile characterized by acceleration and deceleration phases.Our results show that the skyrmion Hall effect is significantly modulated on nanotubes compared to planar models,with specific dependencies on the spin-wave parameters.These findings provide insights into skyrmion manipulation for spintronic applications,highlighting the potential for high-speed and efficient information transport in magnonic devices.

Lap-Shear Performance of Weld-Bonded Mg Alloy and Austenitic Stainless Steel in Three-Sheet Stack-Up

With the growing interest in utilizing Mg and austenitic stainless steel(ASS)in the automotive sector,joining them together in three-sheet configuration is inevitable.However,achieving this task presents considerable challenges due to the large differences in their physical,metallurgical and mechanical properties.To overcome these challenges,the feasibility of using weld-bonding to join Mg alloy/ASS/ASS was investigated.The nugget formation,interface characteristics,microstructure and mechanical properties of the joints were investigated.The results show that the connection between the Mg alloy and upper ASS was achieved through the combined effect of the cured adhesive and weld-brazing in the weld zone.On the other hand,a metallurgical bond was formed at the ASS/ASS interface.The Mg nugget microstructure exhibited fine columar grains composed predominantly of primaryα-Mg grains along with a eutectic mixture ofα-Mg andβ-Mg17Al12.The nugget formed at the ASS/ASS interface consisted largely of columnar grains of austenite,with some equiaxed dendritic grains formed at the centerline of the joint.The weld-bonded joints exhibited an average peak load and energy absorption of about 8.5 kN and 17 J,respectively(the conventional RSW joints failed with minimal or no load application).The failure mode of the joints changed with increasing welding current from interfacial failure via the Mg nugget/upper ASS interface to partial interfacial failure(part of the Mg nugget was pulled out of the Mg sheet).Both failure modes were accompanied by cohesive failure in the adhesive zone.

Combining ability of Egyptian cotton(Gossypium barbadense L.)reveals genetic potential for improved yield and fiber quality

Background As the most widely cultivated fiber crop,cotton production depends on hybridization to unlock the yield potential of current varieties.A deep understanding of genetic dissection is crucial for the cultivation of enhanced hybrid plants with desired traits,such as high yield and fine fiber quality.In this study,the general combining ability(GCA)and specific combining ability(SCA)of yield and fiber quality of nine cotton parents(six lines and three testers)and eighteen F1 crosses produced using a line×tester mating design were analyzed.Results The results revealed significant effects of genotypes,parents,crosses,and interactions between parents and crosses for most of the studied traits.Moreover,the effects of both additive and non-additive gene actions played a notably significant role in the inheritance of most of the yield and fiber quality attributes.The F1 hybrids of(Giza 90×Aust)×Giza 86,Uzbekistan 1×Giza 97,and Giza 96×Giza 97 demonstrated superior performance due to their favorable integration of high yield attributes and premium fiber quality characteristics.Path analysis revealed that lint yield has the highest positive direct effect on seed cotton yield,while lint percentage showed the highest negative direct effect on seed cotton yield.Principal component analysis identified specific parents and hybrids associated with higher cotton yield,fiber quality,and other agronomic traits.Conclusion This study provides insights into identifying potential single-and three-way cross hybrids with superior cotton yield and fiber quality characteristics,laying a foundation for future research on improving fiber quality in cotton.

Severe Cut Throat Injury in a Child: A Case Report and Review of Literature

Background: Cut-throat injury is a potentially fatal condition that may be associated with serious morbidity and mortality. The neck region is particularly at risk of serious injuries due to the location of vital structures, including nerves, viscera, and major vessels. Although cut-throat injury is said to be rare in children, its occurrence has been reported in some series. Management of this condition requires a multidisciplinary approach for a better outcome. Aim: The aim of this report is to highlight the successful management of an alarming case of severe cut-throat injury with associated laryngeal injury in a child. Case presentation: A 12-year-old boy presented with a cut-throat following an assault by an unknown person. Examination revealed an acutely ill child, conscious but pale. He sustained a deep transverse laceration that transected the thyroid cartilage, exposing the laryngeal cavity. An assessment of Zone II penetrating neck injury was made. He was resuscitated, and had emergency neck exploration, tracheostomy, and repair of the injuries. The patient was followed up for 6 months, and had a good voice outcome, with no significant complication. Conclusion: Cut-throat injury is rare in children. But it is a potentially life-threatening condition. It is therefore important to recognize this entity and develop effective protocol of management in our environment.

Liver cell cancer surveillance practice in Nigeria:Pitfalls and future prospects

Hepatocellular carcinoma(HCC)is a disease of public health concern in Nigeria,with chronic hepatitis B and C infections contributing most to the disease burden.Despite the increasing incidence of HCC,surveillance practices for early diagnosis and possible cure are not deeply rooted in the country.This article aims to review the current status of HCC surveillance in Nigeria,stressing the encounters,breaches,and potential prospects.Several factors,such as limited tools for screening and diagnostics,insufficient infrastructure,and low cognizance among the doctors,and the general public affect the surveillance practices for HCC in Nigeria.Moreover,the lack of standardized guidelines and protocols for HCC surveillance further intensifies the suboptimal diagnosis and treatment.Nevertheless,there are opportunities for refining surveillance practices in the country.This would be achieved through boosted public health sensitization campaigns,integrating HCC screening into routine clinical services,and leveraging technological developments for early detection and monitoring.Furthermore,collaboration between government agencies,healthcare providers,and international organizations can facilitate the development of comprehensive HCC surveillance programs person-alized to the Nigerian setting.Thus,HCC surveillance practice faces substantial challenges.By addressing the drawbacks and leveraging prospects,Nigeria can improve HCC surveillance,with subsequent improved outcomes for individuals at risk of developing the disease.

Dengue outbreaks in northern Nigeria: Evaluating the recommended Takeda vaccine and future prevention strategies

Dengue fever,caused by the dengue virus(DENV),poses a significant public health challenge globally,with Nigeria experiencing sporadic outbreaks.A clear understanding of the dengue burden has not been achieved in Nigeria,just as in other African countries.Understanding the epidemiology and burden of dengue fever is essential for effective prevention and control strategies.This paper examines the recent dengue outbreaks in northern Nigeria,particularly in Sokoto state,and evaluates the recommended Takeda dengue vaccine(TDV)along with future prevention strategies.Despite limited surveillance and underreporting,dengue fever is endemic in Nigeria(with over 5 million cases and 5000 dengue-related deaths in 2023),with recent outbreaks indicating a growing concern.The TDV,a live attenuated tetravalent vaccine,has shown promise in preventing dengue fever,but challenges such as vaccine acceptance and access-ibility need to be addressed.Global urbanization contributes to the disease's spread,which is influenced by factors such as population density,cultural beliefs,water storage practices,hygiene,and water supply accessibility.Future prevention strategies must focus on government intervention,community practices,and innovative vector control measures to mitigate the spread of DENV in Nigeria.This study will serve as a valuable reference for policy-makers,researchers,and clinicians in the management and control of DENV in Nigeria and Africa as a whole.

Epidemiology of Mpox Outbreaks and Implications for Surveillance in Imo State, Nigeria

Mpox disease is caused by a double-stranded DNA virus, genus Orthopoxvirus of the family Poxviridae. The incubation period is usually 6 to 13 days but can range from 5 to 21 days while symptoms and signs may persist for 2 to 5 weeks. Although, the clinical features are usually less severe when compared to the deadly smallpox, the disease can be fatal with case fatality rate between 1% and 10%. In Imo State, Nigeria, there has been a changing epidemiology of the disease in the last 6 years and the frequency and geographic distribution of cases have progressively increased. This study aims to conduct a review of the disease epidemiology between 2017 and 2023 and implications for surveillance in Imo State. Surveillance data from the Surveillance Outbreak Response and Management System (SORMAS) was extracted between January 2017 and December 2023 across the 27 Local Government Areas (LGAs) of Imo State. A line list of 231 suspected cases was downloaded into an excel template and analyzed using SPSS® version 20 software. Analysis was done using descriptive statistics and associations were tested using Fischer’s exact at 0.05 level of significance. Of the 231 suspected cases, 57.1% (132) were males, 42.9% (99) were females and the modal age group was between the ages of 0 - 4 (32.5%). Eight (8) LGAs (districts) accounted for 71% (n = 164) of all the suspected cases. 21.2% (49) were confirmed positive, 27 males (55.1%) and 22 females (44.9%) (p > 0.05). Modal age group was 20 - 24 (22.4%, n = 11), 18% (9) were children under 14 years, p > 0.05. Case fatality rate was 8% (n = 4). There was no significant association between mortality and age group. Five (5) LGAs accounted for about 60% (29) of all confirmed cases. These LGAs contribute only 20% to the total population in the State. Only 5.6% and 4% of suspected and confirmed cases, respectively, had knowledge of contact with an infectious source. The study described the epidemiology of Mpox outbreaks between 2017 and 2023 and the findings have significant implications on detection and outbreak response activities.

Ethmoidal Polyposis, Adenoid Hypertrophy and Tympanic Membrane Perforation—A Case Report

Background: Ethmoidal polyposis coexisting with adenoid enlargement and tympanic membrane perforation is a rare condition in otolaryngological practice. Evidences have shown that antrochoanal polyp often times coexists with adenoid enlargement especially in the young which was in sharp contrast to ethmoidal polyposis occurring in the presence of adenoid enlargement. Moreover, the hidden location of nasopharynx housing the adenoids, coupled with the masking effect of bilateral sinonasal polyps, leads to inadvertent misdiagnosis of this complex pathology with subsequent difficulty in providing effective management. Case Presentation: A 24 year-old lady presented with recurrent bilateral nasal obstruction that became persistent associated with nasal discharge and anosmia. She also had recurrent right otorrhoea with associated hearing loss. Diagnostic rigid nasal endoscopy revealed mucoid discharge with bilateral polypoid masses filling both nasal cavities. Otoendoscopic finding revealed a small (about 5%) central tympanic membrane perforation. A clinical assessment of chronic rhinosinusitis with nasal polyposis complicated by chronic suppurative otitis media (CSOM) was made. A non-contrast CT scan of the paranasal sinuses showed isodense lesions in the nasal cavities, all paranasal sinuses and the entire nasopharynx. She had endoscopic sinus surgery and a nasopharyngeal clearance biopsy. The nasal, paranasal and nasopharyngeal masses had histologic confirmation of inflammatory nasal polyps and lymphoid (adenoid) hyperplasia respectively. Her condition improved remarkably with subsequent medical treatment. She was followed up for 8 months and no recurrence was observed. Conclusion: Sinonasal polyposis can coexist with adenoid hypertrophy and middle ear disease as a single pathological condition. Hence, a high index of suspicion and thorough evaluation become necessary for making timely diagnoses and instituting effective management.

Comparison of Blood Pressure Patterns of Teaching and Non-Teaching Staff of a Nigerian University

Objective: Differences in jobs descriptions and responsibilities may contribute to varying degree of exposure to diseases including high blood pressure. There is dearth of studies comparing blood pressure patterns and anthropometric parameters between teaching and non-teaching staff of university. Therefore, this study was designed to assess and compare the blood pressure and the anthropometric parameters of both teaching and non-teaching staff of a Nigerian university. Materials and Methods: A cross-sectional study was conducted to assess blood pressure pattern and anthropometric parameters among 324 apparently healthy teaching (n = 120) and non-teaching (n = 202) staff of Obafemi Awolowo University, Ile-Ife, Nigeria. Anthropometric parameters including height, weight and hip and waist circumferences were measured. Blood pressure was measured thrice during office hours (9.00 - 11.00 hours) using standard procedures and hypertension was defined as ≥140 ≥90 mmHg. Descriptive and inferential statistics were used to analyze the data at p < 0.05 alpha level. Results: The mean of ages of teaching and non-teaching staff were 46.8 ± 9.8 and 45.6 ± 10.9 years. The prevalence of high blood pressure was 34.9% with a distribution of teaching to non-teaching rate of 20.1% and 14.8% respectively. There were significant correlations between blood pressure and each of weight, body mass index and waist circumference in both groups (p < 0.05). Conclusion: Prevalence of high blood pressure was higher among teaching than non-teaching staff and significant correlations were found between blood pressure and some anthropometric parameters. Public health including regular physical activity enlightenment programmes to reduce blood pressure is recommended.

A Comparison of Quality of Life, Medication Side-Effect and Adherence among Schizophrenia Patients on Conventional versus Atypical Antipsychotics

Quality of life (QoL) is becoming a widely accepted schizophrenia management outcome. But it is still not very clear if there are any significant differences between the conventional and atypical antipsychotics in terms of QoL improvement among people with schizophrenia (PWS). It is also imperative that antipsychotic drug-related factors, such as medication adherence and side-effect, which could directly or indirectly affect the QoL of PWS, are determined and compared among PWS on different classes of the drugs. Data were collected on Socio-demographic Characteristics, Quality of Life and Medication adherence using Socio-demographic and Schizophrenia Clinical Characteristics questionnaire, World Health Organization Quality of Life (WHOQoL)-Brief, and Morisky Medication Adherence Scale (MMAS) respectively from 250 respondents attending a tertiary health center’s Psychiatric clinic in Kano, Nigeria. Although PWS on the two classes of antipsychotic drugs showed inequalities in different aspects and domains of QoL, as well as in the levels of adherence and side-effects, the differences were all insignificant. However, presence of drug side effects was significantly associated with lower health-related QoL in the conventional antipsychotics group (p = 0.001), and lower score in the physical domain of QoL in the atypical antipsychotics group (p = 0.044). Medication adherence was found to be associated with better scores in different domains of QoL in both groups of PWS. There are no significant differences in terms of QoL, medication side-effect and adherence among PWS on the two classes of antipsychotics. However, drug side-effects and adherence were significantly and respectively associated with lower and higher scores in different domains of QoL in both groups.

Catatonia: Cavum Septum Pellucidum and Vergae, a Cause or a Coincidence?

Background: Many studies in the 20th century have reported an association between Schizophrenia and Catatonia. Structural brain abnormalities have also been found in many psychotic illnesses, including schizophrenia and there are findings of association of large ventricles with chronic and deteriorating psychosis. It is possible that a large ventricular system may increase the likelihood of catatonia with a chronic course. Cavum Septum Pellucidum (CSP) and Cavum Vergae (CV) are structural abnormalities that have been associated with Schizophrenia. This is a case report of the presence of persistent CSP and CV in a patient diagnosed with schizophrenia with catatonia. Conclusion: Although there are several reports of the findings of a persistent large CSP and CV in patients with Schizophrenia, it is questionable whether the CSP and CV are the cause of the Catatonia or their occurrence is a mere coincidence.

Rheological and Morphological Characterization of Modified Bitumen with Cup Lump Rubber

Pure bitumen is not suitable for heavy traffic loads;hence modifiers are used to improve the bitumen performance.Recently,cup lump rubber(CLR)has become a preferred modifier due to its outstanding performance and less cost.However,little is known about the interactions between CLR and bitumen.Thus,this study investigates the behavior of bitumen with CLR.Four percentages of CLR(2.5%,5.0%,7.5%,and 10.0%by weight of bitumen)were used to modify conventional 60/70 penetration grade bitumen.The modified bitumen was evaluated through different laboratory testing such as dynamic shear rheometer,rotational viscosity,softening point,bending beam rheometer,ductility,and elastic recovery.The testing results show that the addition of CLR increased the bitumen’s rutting resistance by 3 PG grades at high temperatures.At low pavement temperatures,the cup lump rubber modified bitumen(CMB)can withstand up to−34℃.Fourier Transform Infrared(FTIR)analysis shows that the Aromaticity index at 1600 cm^(−1) rose as the CLR percentage increased,indicating the formation of a binder with a compact structure.This is expected to improve the elasticity of bitumen throughπ-πinteractions.Atomic Force Microscopy(AFM)results showed the Catana phase increased in size and quantity at 5.0%and 7.5%CLR content.While contact angle measurement revealed that the binders are hydrophobic and tend to repel the dropped water on the bitumen surface.

GIS Mapping, Biomonitoring and Distribution of Heavy Metal Concentrations Using Neem (Azadirachta indica) Bark in Makurdi Town, Benue State, Nigeria

The present work determined the concentration and spatial distribution of heavy metals (As, Hg, Cr, Cd and Pb) in soil samples from Makurdi and its environs using geographic information system (GIS). The specific objective is to produce the spatial distribution maps showing the spatial distribution of toxic heavy metals in the study area. Inverse Distance Weighting (IDW), a GIS technique was used to produce dotted maps showing the spatial distribution of heavy metals in neem bark for better visualization of contamination zones and non-contamination zones. The map reveals few hotspot areas showing areas of high concentrations of the heavy metals investigated which were identified in red colours, the following concentration ranges were obtained;As (4.71 - 6.43 mg/kg), Cd (13.9 - 16.84 mg/kg), Cr (46.3 - 60.84 mg/kg), Hg (3.70 - 5.05 mg/kg) and Pb (24.02 - 31.34 mg/kg). These hotspot areas were found close to business outlets, fuel filling and service stations, farm sites where the application of fertilizers and pesticides were persistent coupled with heavy traffic of vehicles and other machinery which was associated with As, Hg, Cd, Pb and Cr been released into the environment thus, suggesting anthropogenic activities controlling the concentration of these heavy metals in the study areas. The cumulative effect of these heavy metals into the barks of neem could pose as danger, because this plant is used as herbs in folk medicine.

A Prospective Study on the Incidence and Predictors of Postpartum Depression among Pregnant Women Attending an Antenatal Clinic in Kano, Northern Nigeria

Depressive disorder is a major contributor to years lived with disability (YLD) globally. It is estimated that 13% of all women experience the disorder in the first year postpartum. Postpartum depression (PPD) has significant implications to the physical and mental wellbeing of both the mother and her baby. Only non-depressed pregnant women (score of ≤ 6 on Edinburgh Postnatal Depression Scale) were recruited into this study. Data collection was done at 2 different stages;at recruitment stage (during the third trimester of pregnancy) and at the follow up stage (4th - 6th week postpartum). During the recruitment stage, intimate partner violence (IPV) and level of social support perception, among the women, were assessed using Hurt Insult Threaten Scream (HITS) and Multidimensional Scale of Perceived Social Support (MSPSS) questionnaires respectively. While at the follow up stage, the Obstetric questionnaire and Mini International Neuropsychiatric Interview (MINI-7) were used respectively to obtain obstetric-related data and to diagnose for occurrence of depression. The incidence of PPD was found to be 16.34%. Several factors such as level of education, husband’s socioeconomic status, stressful life events, low perception of social support, obstetric instrumentation and not having a baby of preferred gender were significantly associated with PPD. Positive predictors of PPD included not practicing breast feeding (OR = 186.72, 95% CI = 8.32 - 4188.35), family history of mental illness (OR = 4.95, 95% CI = 1.04 - 23.81) and pregnancy lasting beyond 40 weeks (OR = 7.26, 95% CI = 1.51 - 34.88). High incidence of PPD with numerous associated but largely modifiable risk factors call for more proactive measures, such as PPD screening among pregnant women.

The Imperative of Inter-Modal Transport System in Nigeria: A Case Study of Asaba and Onitsha Transportation System

Transport system in Nigeria is predominantly uni-modal as it is estimated that over ninety per cent of goods and passengers are transported by road.The over-reliance on road transport for the transportation of bulk of goods and people has contributed greatly to the deterioration of Nigeria’s roads and the attendant increase in road maintenance costs.Researches by scholars have revealed that a single means of transport cannot adequately serve the intra and inter-transport needs of the majority of people living in urban cities.Asaba and Onitsha located at the banks of river Niger have outlets for water-based transport services,which are yet to be fully developed and integrated with the dominant road transport system.Bulky goods that arrived by sea are best transported from the port through the waterways to inland ports.The Onitsha port,which was established in the 1980s has not been functioning and this makes road transport the only option for transportation of goods and people between the two cities.It is against this background,that this paper surveys the transport modes in the two cities and advocates the need for inter-modal transport modes that would ensure seamless movement of people and goods between the two cities and with other parts of the country.The paper submits that for the two cities to derive full benefits of the different transport modes,there is need for efficient inter-modal transport systems linking the two cities and regions in order to minimize the frequent chaotic traffic congestion on the Niger bridge.The optimal utilization of inter-modal transport modes would enable each transport mode to perform its distinctive roles which would lead to faster transportation of passengers and goods as well as ensure reduction in transport costs.The paper also proffers ways of achieving an efficient inter-modal transport system between Asaba and Onitsha and Nigeria at large.

Analytical study of silane-based and wax-based additives on the interfacial bonding characteristics between natural rubber modified binder and different aggregate types

The modification of asphalt binder with natural rubber latex(NR)significantly improves the rutting and fatigue resistance of asphalt mixtures.However,NR-modified binder is prone to low workability and wettability due to its high viscosity.Therefore,this research focuses on examining the influences of silane and wax-based additives on the wettability of natural rubber-modified binders and the binder-aggregates adhesion performances.In this study,experimental and analytical approaches were used.The contact angles of asphalt binder were measured using a goniometer through the sessile drop method with three solvents:deionised water,formamide,and glycerol.The Cþþalgorithm was adopted to compute the surface free energy(SFE)elements of the asphalt binder.Analytical methods were employed to analyse the results based on the Young-Dupre equation,followed by linear regression to establish a correlation between the compatibility ratio(CR)and the SFE components.The results inferred that modified asphalt binders with additives possessed improved moisture resistance,wherein dry work adhesion values were less than 210 mJ/m^(2)under granite interfaces,whereas the limestone interface exhibited higher dry adhesion values of 340 mJ/m^(2)and below.Similar performance results were observed under wet adhesion conditions;with granite wet adhesive values observed below 120 mJ/m^(2),while limestone wet adhesion values were ascertained below 180 mJ/m^(2)for all tested samples and conditions.According to the spread–ability coefficient results,the limestone interface has greater spread-ability than granite interfaces.Meanwhile,compatibility ratio values indicated better compatibility of 1.9 or higher for tested samples under granite interfaces,whereas compatibility values of 1.7 and below were observed under limestone interfaces.