bluuebunny/crossref_metadata_2025 huggingface dataset:
Overview of Composite Materials from Green Product in Mechanical Application
Authors: Kilanko O. , Babaremu K.O. , Fayomi O. S. I. , Akande I.G.
Published: February 2021

Green composites have gotten a lot of awareness in the composite industry lately because the whole world is driving toward sustainability whereas conventional composites are usually prepared from petroleum products which are usually non-degradable and result in environmental pollution. This paper presents a succinct review of the composite materials produced from green composites with a potential of being applicable in automotive body parts, aircraft body parts, medicine, construction etc. The review classifies the different research works done into six groups, then identifies gaps in research with the aim of charting a course for future researchers. Also, the review is very essential to manufacturers as they can be kept abreast with the latest developments in green composites which could replace some of the conventional composites used in the manufacturing industry.
Influence of Transition Metal Doping on the Structural and Electronic Behaviour of Quaternary Double Perovskite, Cs2AgInCl6, using First-Principles Calculations
Authors: Ogunniranye I. B. , Oyewande O. E. , Atsue T. , Usikalu M.
Published: February 2021

Recently, direct bandgap double perovskites are becoming more popular among researchers in the photovoltaic community owing to their potential to address issues of lead (Pb) toxicity and structural instability inherent in lead halide (simple) perovskites. In this study, In-Ag based direct bandgap double perovskite, Cs2AgInCl6 (CAIC), is treated with transition metal doping to improve its material properties. Investigations of structural and electronic properties of Cu-doped CAIC, Cs2Ag1−xCuxInCl6, are done using ab-initio calculations with density functional theory (DFT) and virtual crystal approximation (VCA). With the introduction of Cu-dopant, obtained results show improvement in the structural and electronic behaviour of CAIC. Based on obtained results, transition metal (Cu) doping is a viable means of treating double perovskites - by tuning their material properties suitable for an extensive range of photovoltaics, solar cells and optoelectronics.
Adopting Hybrid Energy Technology for Carbon Emissions Reduction in Nigeria’s Telecommunications Industry
Authors: Gershon O , Agbene E
Published: February 2021

Telecoms cell sites, powered by petrol and diesel generators, have high carbon footprints and contribute increasingly to global warming, and thereby climate change. Utilizing primary data from telecom cell sites of a major operator in Nigeria, this study empirically determines the firm’s CO2 emissions and considers how hybrid energy technology (HET) could be adopted to reduce the industry’s carbon footprint. Data of fuel utilization in power generation are applied to compute CO2 emissions. Towards reducing the firm’s and industry’semissions, hybrid energy technology options for incorporating solarin the energy mix are considered. Hybrid energy technologies optimize existing hydrocarbon generating plants with photovoltaic panels and storage batteries to provide minimum capacities for powering the electronic devises. Results show that HET opportunities exist for most telecom firms’ cell sites given Nigeria’s geographical advantage to access sunlight. In addition, through the adoption of hybrid energy, average daily fuel usage is reduced by 50% (apart from periods of peak demand and weather disruptions). If adopted by the major telecoms operators, as recommended, greenhouse gas emissions level in the industry will reduce significantly.A few notable challenges are highlighted in the paper. However, job creation in the renewable energy industry is a notable advantage of transforming power generation in the telecommunications industry.
The use of Waste Duck Eggshells for Sustainable Energy Production
Authors: Ayoola A.A. , Adeyemi G. , Raji O. , Babalola A.
Published: February 2021

In this study, waste duck eggshells were processed into high grade CaOheterogenous catalyst for the esterification-transesterification of palm kernel oil (PKO) to obtain biodiesel. The production processes involved are calcination of duck eggshells into CaO, XRD and XRF analysis of CaO produced, PKO fatty acid components determination, transesterification of the esterified PKO and the formulation of a suitable model. High biodiesel yield of 84% was obtained at catalyst concentration of 9 wt./wt. %, reaction time of 2 hours and methanol/oil mole ratio of 13, using CaO catalyst (derived from duck eggshell). The good quality of biodiesel produced was ascertained by its properties that fall within ASTM specifications (kinematic viscosity of 4.1 mm2/s, flash point of 195°C, density of 869kg/m3, water content of 0.045 v/v %).
Pilot Plant Design of 1kg Biodiesel Production using Waste Soybean Oil
Authors: Ayoola A.A. , Alagbe E.E. , Makinwa T.A.
Published: February 2021

As part of the efforts in attaining the commercialisation of biodiesel production in Nigeria, this research work considers a pilot plant design for the production of 1kg biodiesel, using waste soybean oil (WSO). CHEMCAD 7.1.2 software was utilised for the plant design and the process flow diagram revealed that four (4) pumps, four (4) heaters, two (2) separators, one (1) drying equipment and two (2) reactors were involved. Also, the simplified and simulated 1kg biodiesel production design plant showed that 0.0513kg/hr of methanol and 0.1800kg/hr of 0.1M H2SO4 would be required during the esterification process. And 0.6921kg/hr of methanol, 0.9870kg/hr of WSO as well as 0.1880kg/hr of KOH catalyst would be required for the transesterification process. That is the results obtained serve as template for the simulation of process design plants of varied production capacities. This is a good attempt in the ease of attainment of the commercialisation of biodiesel production in Nigeria.
Nigeria’s quest for alternative clean energy through biofuels: an assessment
Authors: Nwozor Agaptus , Owoeye Gbenga , Olowojolu Olankunle , Ake Modupe , Adedire Solomon , Ogundele Oluwaseun
Published: February 2021

Nigeria is rich in renewable energy resources, including diverse biomasses. However, this enormous endowment in renewable energy resources has not played any significant role in the country’s energy mix. Nigeria is majorly reliant on its non-renewable sources to meet its energy needs. In pursuit of its commitment to transit to alternative clean energy, Nigeria developed the biofuels policy document in 2007. The major aspiration of the policy is to harness the country’s biomass potentials and deploy same to meeting Nigeria’s energy needs. This paper assesses the state of the biofuels sector vis-à-vis the stated aspirations of the Nigerian state as captured in the biofuels policy document. In doing so, this paper uses primary data generated from key informant interviews and augmented with secondary data. It finds a disconnect between the aspirations of the biofuels policy document and the actual state of the biofuels sector. In other words, the biofuels sector has no discernible contribution to Nigeria’s energy mix. The recommendation of this paper is in the realm of rejigging the biofuels policy in order to extract greater government commitment in evolving national capacity for biofuels development.
Atomistic Simulations of MAPbI Pm-3m Using First-Principles Calculations
Authors: Adegboyega Oluwasogo A. , Oyewande Oluwole E. , Micheal Emeka , Usikalu M.R.
Published: February 2021

The unprecedented fast increase in power conversion efficiency seen in photovoltaic devices based onhybrid halide perovskites have drawn significant research interests. Recent researches in this area have focused on finding different perovskites with better properties, especially stability. Atomistic simulations based on density functional theory were performed in order to investigate the electronic properties of MAPbIPm-3m using Projected Augmented Wave (PAW) pseudopotential withmodified Perdew-Burke-Ernzerhof (PBE) for solidsfunctional withingeneralized gradient approximation (GGA) as implemented in QUANTUM ESPRESSO simulation software. The results obtained gave 6.1248Åas the lattice parameter and 1.1019eVas the bandgapinMAPbIpm-3m perovskite, which shows the perovskite has a direct bandgap.
Utilization of property valuation software among estate surveying and valuation firms in Lagos state, Nigeria
Authors: Ogunnowo O. E. , Iroham C. O. , Oloke O. C.
Published: February 2021

In the era of sophistication in conducting professional assignments, there have been no study geared towards assessing the utilization of valuation software in property valuation. This study therefore investigated the application of property valuation software among Estate Surveyors and Valuers (ESVs) in Lagos Metropolis. 151 Estate Surveying and Valuation (ESV) firms represented the sample size. Data was analyzed using descriptive statistics and frequency count with the aid of Statistical Package for Social Sciences (SPSS). It was revealed that almost 70% of ESV firms do not readily use property valuation software, even the ones known to them. The study therefore encourages ESVs to utilize such software so as to ease their mode of operations.
Evaluation of Permeability Impairment Due to Surfactant Flooding
Authors: Abraham D. V. , Orodu O. D. , Efeovbokhan V. E. , Okoro E. E., , Ojo T. I. , Bolujo E. O.
Published: February 2021

In the course of chemical flooding of crude oil reservoirs with surfactants, retention of surfactant particles in the pores of the reservoir rock can cause a major reduction of the reservoir permeability. This can cause serious problems thus unfavourably influencing the economics of oil recovery. An appropriate assessment of the reduction in permeability is essential for the recovery of hydrocarbons. During tertiary recovery of crude oil, a critical evaluation of formation damage is necessary to evade operating costs, as the reservoir rock is extremely sensitive to chemicals injected. The extent to which permeability is reduced cannot be comprehensive for core field scales; it is consequently paramount to study the reduction in the permeability of a core at laboratory scale before field scale estimation. In this paper, an experimental investigation on the reduction in permeability after surfactant injection cores is presented. Surfactants were used to flood the core samples. The permeability of the cores was calculated at the beginning and end of every flood by measuring the differential pressure during surfactant flooding of the cores. From the results, it is evident that there is a strong influence of surfactants on the process of adsorption on reservoir rocks and consequently leading to reduction in permeability.
Geoenvironmental and health risks associated with toxic metals in goldmine site of Iperindo, southwestern Nigeria
Authors: Adewoye A. O. , Oloyede D , Adewoye S.O.
Published: February 2021

Mineral exploitation enhances the nation’s economic growth and development but poses serious threats to the environment thereby leading to ecological imbalances and public health risks. This study evaluates heavy metal pollution in an abandoned gold mining site of Iperindo, Southwest Nigeria and associated environmental and health risks were investigated. Soil samples collected at the site were subjected to a total digestion technique and analyzed for metals (As, Pb, Cd, Cr, Cu, Zn, Co, Ni, and Fe) using AAS. Only SS15 had a baseline pollution level while all other sampling points had significant heavy metal pollution. Generally, the analysis showed that 33.3% and 66.7% of the sites are included in the unpolluted and moderately polluted classes respectively for As, Cr, Cu, Co, and Ni. For Cd and Zn, 13.3% of the sites were in unpolluted class while it was 40.0% and 66.7% for Pb and Fe respectively. By implication, the highest ecological risk was at SS3 while metal that posed the highest ecological risk was Cd. HQ estimated for all metals via ingestion and dermal pathways for both adults and children were > 1 but < 1 via inhalation pathways in both age groups. However, the values were greater in children than adults. This suggested that oral and dermal exposures to As, Pb, Cd, Cr, Cu, Zn, Co, Ni and Fe in the soil of the study area would elicit non-carcinogenic adverse health hazard. This result shows the critical need to carry out remediation of the study site despite the abandonment of mining operations to protect possible health hazards, particularly to children.
X-Ray Imaging Techniques Appraisal: Pathway to Sustainable Health Status
Authors: Achuka J. A. , Usikalu M. R. , Aweda M. A. , Olowoyeye O. A. , Enemuwe C. A. , Babarimisa I. O.
Published: February 2021

There is possibility for sustainable healthcare delivery through the implementation of periodic x-ray imaging techniques appraisal. The aim of this study is to evaluate the x-ray imaging techniques in the study area in order to promote sustainable health status of the populace. Data for this study was collected from 12 major healthcare institutions located in Southwest Nigeria using self-structured form. The study centres were designated using S1 to S12. The x-ray imaging techniques in the study area were radiography, computed tomography (CT), mammography and fluoroscopy. Radiography machine was available in all the study centres while 75 % of the centres had CT scanners, 50 % had mammography machines and 25 % had fluoroscopy machines. The x-ray imaging centre with the highest number of equipment is Centre S2 while Centre S6 has the least equipment. The outcome of this study implied that x-ray imaging techniques appraisal would boost procurement of more and newer equipment, enhance improved quality and efficiency of the x-ray equipment. Thereby, accord patients accessibility to all the benefits of the modalities x-ray imaging can provide; and consequently promoting patients health status. Hence, this study recommended the implementation of periodic x-ray imaging techniques appraisal.
Measurements of Physiochemical Parameters and Trace Element Concentration of Rock Samples in Ogun State
Authors: Usikalu Mojisola R. , Akinpelu Akinwumi , Lucky-Fiakpa O. , Nmoma J. , Ichoku E.
Published: February 2021

Trace elements occur in tiny quantities but detectatble, in minerals and rocks. They are always less than 1% of the all the minerals. When trace elements’ concentration is low, they become beneficial and aids growth an metabolism but when present at high concentrations begin to pose health risks. This paper aimed at investigating and analyzing the pH, electrical conductivity, and trace element concentrations in the rocks samples collected from twenty local government headquarters of Ogun state, using a pH meter, an atomic absorption spectrometer and an electrical conductivity meter, respectively. The measured pH ranged between 6.63 to7.34, which suggests that the rocks in these areas are neutral. The electrical conductivity estimated varied between 46.3 and 598µScm−1, with Ewekoro having the highest conductivity, which may be due to the accumulation of limestone in this area. It was noticed that all the elements were present in minute quantities except iron (Fe), which was present in high concentration that exceeded the recommended value. It was thenconcluded that the rocks in the study area are neutral and contain a high concentration of iron.
The trend of collapse of buildings in concrete materials in Lagos State, Nigeria (2013-2019)
Authors: Ede Anthony N. , Akpabot Akpabot I. , Oyebisi Solomon O. , Olofinnade Oluwarotimi M. , Okeke Chukwueloka A. , Oyeyemi Kehinde D. , Ugwu Emmanuel I. , Gambo Fiyin
Published: February 2021

Buildings are essential structures that provide mankind with accommodation in the form of offices, factories, residences, etc. Building Infrastructure aid to increase the Gross domestic product of nations by meeting the present needs as well as helping in the reduction of future deficiencies. Unfortunately, in developing countries like Nigeria, regular occurrence of collapse of buildings in concrete materials have dealt a terrible blow to the nation, leading to losses in the form of death and damage to properties. This study aims to show the trend within the period of 2013 to 2019. This study used statistical methods to assess the fatality rate, types of buildings affected, frequency of occurrences and the causative factors. The result indicates that the year2017 witnessed 14 collapse incidences making it the highest within the study period in Lagos state. Furthermore, 204 persons lost their lives in 2014, making it the highest within the period. The results obtained showed that the risk of collapse and fatality rises as the building height goes up and when unauthorized floors are added to an existing building.
Fire Risk Exposure and Preparedness of Peri-Urban Neighbourhoods in Ibadan, Oyo State, Nigeria
Authors: Oloke O.C. , Oluwunmi O.A. , Oyeyemi K.D. , Ayedun C.A. , Peter N.J.
Published: February 2021

This study assessed the exposure of urban neighbourhoods to environmental hazards generally and fire risk in particular in Ibadan. Lagelu, a rapidly urbanizing local government area was selected for the study with emphasis on Lagelu West Local Development Council. Relevant literatures were review in this regards while structured questionnaires were administered on adult residents of 320 households in the selected peri-urban communities. Respondents opinion were obtained as regards the susceptibility of their communities to different environmental hazards. Data was also obtained from the respondents on the causes/sources of fire risk in their respective neighbourhoods as well as adequacy of fire safety apparatus in the communities. Data were measured on 5-Point likert scale of strongly agreed (5) to strongly disagree (1). Response were analysed with basic tools of mean score, relative importance and interpreted based on cut-off point (as devised in Morenikeji, 2006). The causes of fire and adequacy of community fire safety apparatus were analysed in percentages and presented in tables and bar charts. The study showed that there is a general consensus that the communities are highly vulnerable to the environmental risks identified in the study. It was also revealed that fire outbreak is principally caused by human activities, negligence as well as faulty electrical equipment and power surge. Respondents generally are of the opinion that fire safety apparatus available in the communities are grossly inadequate thereby compounding the vulnerability predicament of these communities. The study therefore recommends amongst others, upgrade of the community road network, provision of firefighting system within the neigbhourhood and enlightenment of residents on fire safety precautions.
Arsenic in agricultural soils and implications for sustainable agriculture
Authors: Kayode O. T , Aizebeokhai A. P. , Odukoya A. M.
Published: February 2021

The concentration of arsenic in agricultural soils has become a global challenge. Arsenic sources in soils can be both anthropogenic and natural. Certain fertilizers can introduce arsenic into the agricultural soil. For this study, soil samples from a commercial farm in southwest Nigeria were analysed using Inductively Coupled Plasma Mass Spectrometry (ICPMS). This study indicates that arsenic concentration in the farm land is fairly normal, with some portion of the farm having higher concentration than the WHO recommended standard limits in agricultural soils. Thus, there is need for immediate intervention to reduce the arsenic concentration in the farm site as arsenic is toxic to both human and crops alike. Measures to reduce arsenic in agricultural soils have been highlighted.
Viability of residential properties in Ota, Ogun state Nigeria using modified break-even valuation technique
Authors: Iroham C. O. , Oni S. A. , Okagbue H. I. , Emetere M. E. , Oluwunmi A. O. , Durodola O.D. , Ajibola M. O. , Ogunnowo O. , Udonquak U. M.
Published: February 2021

Viability appraisal as a veritable tool to guide investors of proposed projects could either be carried out through any of deterministic or probabilistic approach. Both approaches with varied types of techniques have been criticized but still have their relevance in determining the viability of any given project based on required objectives. A review of earlier works on viability appraisal was carried out including that of the Nigerian experience. Observation and required measurements in the property market of the study area, Atan-Ota at Sokoto Road to be precise that lies and situates between latitude 60 40‘29.5716” and longitude 30 11‘52.9908”. Amongst all viability techniques, the break-even viability appraisal technique was adopted for this study based on cost maximization so as to enable investors take decision on the barest minimum production level. The break-even point technique though modified using the Net Present Value (NPV) was utilized in the study area on three residential property types readily purchased. They are the 2 bedroom flat, 3 bedroom flat and 4 bedroom bungalow. It was revealed that the 3 bedroom flat is most viable as it will require the sales of 13.03 units to break-even while 2 bedroom flats will require the sale of 14.69 units to break even. The 4 bedroom bungalow will however require the sales of 17.17 units to break-even. The study thereby recommends that investors focus more on the 3 bedroom housing units in the study area for easiest attainment of the break-even point.
Assessment of Natural Radionuclide Contents in Water and Sediments from Asa-Dam, Ilorin, Nigeria
Authors: Orosun M. M. , Usikalu M. R. , Onumejor C. A. , Akinnagbe D. M. , Orosun O. R , Salawu N. B. , Olasunkanmi N.K. , Akinpelu A. , Adagunodo T. A. , Achuka J. A.
Published: February 2021

Natural radionuclides content of
238U,

232Th and
40Kfor water and sediment samples collected from Asa-dam Ilonn. Nigeria weremeasured using Nal(TI) detector. The mean activity concentration in the water samples were 6.05, 3.23 and 9.65 Bql−1
for
238U,

232Th and
40Krespectively. The mean activity concentration of
238U,

232Th and
40Kmeasured in the sediment samples were 7.57, 8.19 and 73.48 Bql−1
respectively. Theactivity concentration of
40Kwas higher than that of
238U and
232Thfor the water and sediment samples. All measured activity concentration and estimated radiological parameters were below world permissible limit values. Therefore, there may be no serious immediate radiological health burden on the environment and the people using the dam.
Pollution indices and health risk assessment of heavy metals in floodplain of urban catchment of Asa drainage systems, southwestern Nigeria
Authors: Adewoye A.O. , Ajibade T.T. , Adewoye S.O. , Olagunju T.E. , Adagunodo T.A.
Published: February 2021

Urbanization and industrialization have significantly caused deterioration of surface waters. Since there is close association between river quality and its associated floodplain, the later could therefore provide a quality index of the former. This study examines heavy metal concentrations in floodplain sediment of urban catchment of Asa River and assessed associated risks. Samples were collected at 10 points but at interval of 5cm in vertical profile to a depth of 15cm. Atomic Absorption Spectrophotometer (AAS) analyses were done for Pb, Ni, Zn, Fe, Cu and Al. The following computational models were employed for risk analysis; Depth Ratio (DR), Contamination Factor (CF), Degree of Contamination (Cdeg), Geoaccumulation Index (Igeo), Pollution Load Index (PLI), Hazard Quotient (HQ), Hazard Index (HI) and Cancer Risk Index (CRI). Considerable degree of metal contamination was observed with various pollution levels from non-pollution with Ni, through moderate pollution with Pb, to a moderately strong pollution with Zn, Fe, Cu and Al. PLI revealed a baseline pollution level (PL ≈ 1) but contamination factor for each of Zn, Fe and Cu was considerable and may pose ecological threats and by extension, human health. Metal association reveals a positive correlation among all the metals evaluated (p < 0.05) which is suggestive of similar source. HQ via ingestion and dermal routes calculated were > 1 for both children and adult but< 1via inhalation. CRI for lead shows that children arepredisposed to cancer risks than adults. Hence, industrial activities in the urban catchment of Asa River must be monitored for environmental compliance.
Determination of Radon gas in bottled and sachet water in Ile-Ife, Nigeria
Authors: Oni E.A. , Adagunodo T.A. , Adegbite A.A. , Omeje M.
Published: February 2021

The environmental monitoring of radon contents in some bottled and sachet water were carried out, with the aid of an active radon device (RAD7) made by Durridge, USA. This study is aimed to determine the level of radon in selected bottled and sachets water in major market in Ile-Ife, with a view to establishing the health risks that could arise in consumption of the water. The results obtained in this study show that all the water samples were safe for consumption without any health implication from radiological point of view.
Evaluation of the effect of Physicochemical Parameters on the Biodegradation of spent engine oil using selected Oleophilic Bacteria
Authors: Yusuf Olabisi Omolola , Torimiro Nkem , Afolalu Sunday A. , Abioye Abiodun A. , Emetere Moses E. , Alayande Samson O.
Published: February 2021

Pollution emanating from the disposal of the auto-mechanic’s workshop is of significant challenge globally. This study presents an evaluation of physicochemical parameters on Biodegradation of spent engine oil using selected Oleophitic bacteria. The effect of nitrogen sources (Casein, Urea, Ammonium Sulphate and Potassium Nitrate), pH (4-10) and temperature (25°C to 45°C) were varying on the Biodegradation of spent engine oil using isolated hydrocarbon degraders;Klebsiella sp., Acinetobacter sp., Pseudomonas sp., and Bacillus sp obtained from auto-mechanic’s workshops. The assessment of the growth of these hydrocarbon degraders was assessed in Minimal Salt medium (MSM) supplemented with 1% Spent engine oil for seven days. The turbidity of the inoculated MSM was assayed using U.V. Spectrophotometer. The study revealed that the most preferred Nitrogen sources that supported the optimum growth of these hydrocarbon degraders were Casein, while the best pH was 8 and 9. The temperature that supported the optimal growth of the isolates varied with each strain which ranges between 35°C and 40°C. The growth of these bacterial isolates revealed that Biodegradation of the used engine oil is proceeding.
Providing a sustainable framework for academic workspace evaluation: a literature review
Authors: Adenipekun M. T. , Ajibola M. O. , Oluwunmi A. O.
Published: February 2021

This paper aims to articulate the user-centred variables in academic work environment with holistically sustainable Academic Workspace Evaluation (AWE) framework for universities. The paper considers emergent thought on academic workspace with respect to the requirement of users. Based on this point, a broad-review of literature around the variables underpinning academic workspace disposition to users’ conduct is carried out. The study identifies 109 user-centred cognate variables as prerequisite of AWE. These variables fall into three basic units for ease of analysis: the organisation culture, the employees’ work environment, and the academic workspace condition. Each of the three identified units must contribute respectively to meeting the desired condition of workspace in its holistic form. In other words, the success in each unit affects the success of the other two units. Furthermore, the quality of the workspace depends entirely on the corporate interaction and interrelationship of the three units. However, differences in culture, system, process, modes of work operations, purpose and objectives between universities presents difficulties to generating a holistic universal user-centred AWE framework. It is therefore inappropriate to strictly and absolutely adopt a universal framework for academic workspace without the inclusion of local contents for individual university flexibility. The framework is context-based designed to accommodate these local contents within the conventional structure arrangement of respective universities. The proposed AWE framework is capable to generate Universal Minimum Academic Workspace Benchmark Standard (UMAWBS) for use in universities globally.
Engineering Site Investigations using Surface Seismic Refraction Technique
Authors: Adewoyin O. O. , Joshua E.O. , Akinyemi M. L. , Omeje M. , Adagunodo T.A. , Joel E.S.
Published: February 2021

In this study, surface seismic refraction method together with cone penetration test were used to provide 2-dimensional (2D) information of the subsurface geological features. This approach simplified the characterization of the subsurface condition of a relatively large area of land especially when it is required for engineering construction purposes. The results of the seismic refraction method disclosed two geologic layers with seismic velocity ranging between 258 and 3544 m/s. Similarly, the cone penetration test revealed the topsoil to a depth of 6 m as soft and highly compressible formation, which is suspected to be Alluvium. Moreover, at depth between 7 and 10 m into the subsurface, a geomaterial with good geotechnical formation and low compressibility potential was encountered. This geologic formation is suspected to be sandy clay. The results of the two methods were correlated, it was revealed that the depth to the most competent layer in the study area is between 7 and 10 m depth.
The morphology of doubly-clamped graphene nanoribbons
Authors: Brand Christian , Monazam Mohammad R A , Mangler Clemens , Lilach Yigal , Cheshnovsky Ori , Arndt Markus , Kotakoski Jani
Published: February 2021

Understanding the response of micro/nano-patterned graphene to mechanical forces is instrumental for applications such as advanced graphene origami and kirigami. Here, we analyze free-standing nanoribbons milled into single-layer graphene by focused ion beam processing. Using transmission electron microscopy, we show that the length L of the structures determines their morphology. Nanoribbons with L below 300 nm remain mainly flat, whereas longer ribbons exhibit uni-axial crumpling or spontaneous scrolling, a trend that is well reproduced by molecular dynamics simulations. We measure the strain of the ribbons as well as their crystallinity by recording nanometer-resolved convergent beam electron diffraction maps, and show that the beam tails of the focused ion beam cause significant amorphization of the structures adjacent to the cuts. The expansive or compressive strain in the structures remains below 4%. Our measurements provide experimental constraints for the stability of free-standing graphene structures with respect to their geometry, providing guidelines for future applications of patterned graphene.
Natural cuticle-inspired chitin/silk fibroin/cellulose nanocrystal biocomposite films: fabrication and characterization
Authors: Xu Kaimeng , Zhang Yulu , Ye Qian , Wu Jiaxi , Li Qiushi , Su Ganmao , Harper David Paul , Du Guanben , Ye Xiaofei P , Wang Siqun
Published: February 2021

This study aims at developing a green sustainable bio-inspired composite film by combining the flexible chitin/silk fibroin matrix (CT/SF) and the rigid cellulose nanocrystals (CNC) with the multi-layer chiral nematic structure. The effects of CNC concentration on the chemical bonding, optical- and micro-morphology, thermal stability and mechanical properies of chitin/silk fibroin/cellulose nanocrystal (CT/SF/CNC) were comprehensively investigated. The results indicate that a critical concentration for CNC at 2 wt% can display the obvious iridescent color domains of biocomposite films with potential optical functional property. There is a color shift from blue to yellow-red corresponding to the higher concentrations at 3.5 and 5.0 wt%, respectively. The concentration of CNC also affects the transition of conformation of SF from the random to the β-turn as well as the bonding ability between SF and CT. The CT/SF/CNC-3.5 wt% with the excellent optical and mechanical properties as well as the improved thermal stability breaks the conventional conflict between increased strength and compromised ductility. Its tensile strength and elongation at break effectively elevate by 282% and 42%, respectively.
Controllable synthesis of SiC wrapped LDHs to reinforce microwave absorption and exothermic properties of styrene-butadiene-styrene (SBS) polymer modified asphalt
Authors: Li Chao , Zeng Guodong , Zhou Min , Fang Yang , Chen Zongwu , Xu Yishen , Ding Siyin , Yuan Miao , Li Hao , Wu Shaopeng
Published: February 2021

Combination of styrene-butadiene-styrene (SBS) polymer and layered double hydroxides (LDHs) has commonly applied in asphalt to improve anti-ultraviolet aging performance, but it can not afford the reparation of cracks caused by aging of asphalt. Also, few researches focused on the structure and performance changes during synthesis of LDHs. Based on self-healing performance of asphalt, the produced cracks can be repaired by microwave heating. Therefore, the controllable synthesis of traditional microwave absorber SiC to wrap LDHs (SwL) at different temperatures was studied in this paper, and the effects of different SBS/SwL combination on the microwave absorption and exothermic properties of modified asphalt were studied. The SwL was firstly synthesized at 200 °C, 350 °C, 500 °C and 650 °C. Then morphology, phase composition, chemical structure of different SwL were evaluated. Finally, based on different combination of SBS and SwL, the effects of SBS/SwL on the microwave absorption in the frequency band from 1 GHz to 18 GHz and exothermic characteristics at 2.45 GHz of the modified asphalt were analyzed. The results show that SwL can be synthesized successfully, and the processing temperature significantly affects the structure of SwL. The SBS/SwL-200 modified asphalt has the best microwave absorption and exothermic properties. When used in self-healing asphalt, it is more advantageous to choose 200 °C as the synthesis temperature of SwL.
Microstructural and intergranular corrosion properties of Inconel 625 superalloys fabricated using wire arc additive manufacturing
Authors: Guo Chun , Ying Meng , Dang Hengyao , Hu Ruizhang , Chen Feng
Published: February 2021

Inconel 625 superalloy samples were fabricated using wire arc additive manufacturing (WAAM). The phase composition, microstructure, anti-corrosion, and mechanical properties of the Inconel 625 WAAM samples were analyzed. The microstructure of the Inconel 625 WAAM alloy showed good forming quality, no defects, and good metallurgical bonding within the specimens. The metallographic structure exhibited primarily γ-Ni and granular precipitated phases; the average microhardness of the transverse and longitudinal cross-sections of the sample was 243.5 and 243.3 HV0.1, respectively. Yield and tensile strength as well as elongation, decrease in area, and the room-temperature impact values of this alloy were equal to 450 and 736 MPa, 38% and 52%, and 152 J, respectively. The intergranular corrosion test results indicated that the average corrosion rate of the sample is 0.609 mm/year, indicating excellent resistance to intergranular corrosion.
Surface-enhanced Raman scattering effect in binary systems formed by graphene on aluminum plasmonic nanostructures
Authors: González-Campuzano R , Sato-Berrú R Y , Mendoza D
Published: February 2021

Binary systems (BS) formed by graphene (GR) deposited on top of aluminum (Al) nanoconcaves (Al-NC) and Al nanodomes (Al-ND) were synthesized by electrochemical anodization of Al. Using the plasmonic response of Al-NC and Al-ND and the distinctive physical and chemical properties of GR, these BS are proposed as Surface-Enhanced Raman Scattering (SERS) sensors using rhodamine 6G (R6G) as a proof molecule. As expected, the BS significantly enhances Raman signals of R6G molecules in comparison with substrates used as references, also suppressing the fluorescence background of R6G molecules.
Remarks on asymptotic order for the linear wave equation with the scale-invariant damping and mass with 𝐿^{𝑟}-data
Authors: Inui Takahisa , Mizutani Haruya
Published: February 2021

In the present paper, we consider the linear wave equation with the scale-invariant damping and mass. It is known that the global behavior of the solution depends on the size of the coefficients in front of the damping and mass at initial time

t
=
0

t=0

. Indeed, the solution satisfies the similar decay estimate to that of the corresponding heat equation if it is large and to that of the modified wave equation if it is small. In our previous paper, we obtained the scattering result and its asymptotic order for the data in the energy space

H
1

×

L
2

H^1\times L^2

when the coefficients are in the wave regime. In fact, the threshold of the coefficients relies on the spatial decay of the initial data. Namely, it varies depending on

r
r

when the initial data is in

L
r

L^r

(

1
≤
r
>
2

1\leq r > 2

). In the present paper, we will show the scattering result and the asymptotic order in the wave regime for

L
r

L^r

-data, which is wider than the wave regime for the data in the energy space. Moreover, we give an improvement of the asymptotic order obtained in our previous paper for the data in the energy space.
Morse-Smale characteristic foliations and convexity in contact manifolds
Authors: Breen Joseph
Published: February 2021

We generalize a result of Giroux which says that a closed surface in a contact

3
3

-manifold with Morse-Smale characteristic foliation is convex. Specifically, we show that the result holds in contact manifolds of arbitrary dimension. As an application, we show that a particular closed hypersurface introduced by A. Mori is

C

∞

C^{\infty }

-close to a convex hypersurface.
A note on point-finite coverings by balls
Authors: De Bernardi Carlo Alberto
Published: February 2021

We provide an elementary proof of a result by V. P. Fonf and C. Zanco on point-finite coverings of separable Hilbert spaces. Indeed, by using a variation of the famous argument introduced by J. Lindenstrauss and R. R. Phelps [Israel J. Math. 6 (1968), pp. 39–48] to prove that the unit ball of a reflexive infinite-dimensional Banach space has uncountably many extreme points, we prove the following result.

Let

X
X

be an infinite-dimensional Hilbert space satisfying

d
e
n
s

(
X
)
>

2

ℵ
0

\mathrm {dens}(X)>2^{\aleph _0}

, then

X
X

does not admit point-finite coverings by open or closed balls, each of positive radius.

In the second part of the paper, we follow the argument introduced by V. P. Fonf, M. Levin, and C. Zanco in [J. Geom. Anal. 24 (2014), pp. 1891–1897] to prove that the previous result holds also in infinite-dimensional Banach spaces that are both uniformly rotund and uniformly smooth.
Atg15 in Saccharomyces cerevisiae consists of two functionally distinct domains
Authors: Hirata Eri , Shirai Kyo , Kawaoka Tatsuya , Sato Kosuke , Kodama Fumito , Suzuki Kuninori
Published: February 2021

Atg15 is a lipase essential for disintegration of autophagic body membranes. In this study, we found that the N-terminal domain alone can travel to the vacuole via the multivesicular body pathway, and identified residues required for degradation of autophagic bodies in the C-terminal lipase domain.
Fibronectin fibril alignment is established upon initiation of extracellular matrix assembly
Authors: Garrison Carly M. , Schwarzbauer Jean E.
Published: February 2021

Fibronectin (FN) fibril alignment is crucial for tissue function. We show that assembly of aligned fibrils is determined by the polarized localization of matrix assembly sites. Oriented sites progressed into aligned fibrillar adhesions and FN fibrils. TGF-b stimulated aligned FN assembly, providing a mechanism to modulate fibril orientation in vivo.
Underage Adolescents’ Reactions to Adverts for Beer and Spirit Brands and Associations with Higher Risk Drinking and Susceptibility to Drink: A Cross-Sectional Study in the UK
Authors: Boniface S , Critchlow N , Severi K , MacKintosh A M , Hooper L , Thomas C , Vohra J
Published: February 2021

Aims

In the UK, adolescents under the minimum legal purchasing age (<18 years) are aware of a variety of alcohol marketing activities. It is therefore important to examine how such marketing appeals and how it might shape consumption. This study assessed the relationships between positive reactions to alcohol adverts and susceptibility to drink among never drinkers and higher-risk drinking among current drinkers.

Methods

Online cross-sectional survey of 11–17 year olds (n = 2582) in the UK. Adolescents were shown three video alcohol adverts (Fosters Radler/Haig Club Clubman/Smirnoff). Reactions to each were measured by eight scale-items (e.g. 1 = makes [Brand] seem unappealing to 5 = makes [Brand] seem appealing), which were combined into a composite score (coded: positive versus other). Logistic regressions assessed associations between overall positive advert reactions and drinking behaviours.

Results

Half of adolescents had overall positive reactions to the Smirnoff (52%) and Fosters (53%) adverts, and a third (34%) had a positive reaction to the Haig Club advert. Across all three adverts, positive reactions were associated with ~1.5 times increased odds of being susceptible to drink among never drinkers. Among current drinkers, positive reactions to the Foster’s Radler and Haig Club adverts were associated with around 1.4 times increased odds of being a higher-risk drinker.

Conclusions

These alcohol advertisements commonly appealed to underage adolescents, and these reactions were associated with susceptibility among never drinkers and higher-risk consumption among current drinkers. Regulatory consideration should be given to what messages are permitted in alcohol advertising, including international alternatives (e.g. only factual information).
Puerarin plays a protective role in chondrocytes by activating Beclin1-dependent autophagy
Authors: Li Guishuang , Rao Hongming , Xu Weihong
Published: February 2021

Puerarin can protect chondrocytes, whereby ameliorating osteoarthritis. Puerarin also promotes autophagy. Autophagy maintains chondrocyte homeostasis. The role of autophagy in puerarin-protected chondrocytes is unknown. Puerarin promoted chondrocyte autophagy. Puerarin-protected chondrocytes were reversed by autophagy inhibitors and Beclin1 inhibitor. 3-MA or Beclin1 inhibitor in vivo reversed puerarin-ameliorated cartilage damage of osteoarthritis mice. Thus, puerarin can protect chondrocytes through Beclin1-dependent autophagy activation.
Mutant Zp1 impedes incorporation of ZP3 and ZP4 in the zona pellucida, resulting in zona absence and female infertility in rats
Authors: Lv Chao , Huang Hua-Lin , Yi Da-Jing , Peng Tian-Liu , Tan Hang-Jing , Quan Ru-Ping , Deng Hong-Wen , Xiao Hong-Mei
Published: February 2021

The zona pellucida (ZP) plays vital roles in reproductive processes including oogenesis, fertilization, and preimplantation development. Both human and rat ZP consist of four glycoproteins, called ZP1, ZP2, ZP3, and ZP4. Our previous research reported a novel Zp1 mutation in cases of human infertility, associated with an abnormal phenotype involving the absence of the ZP. Here, we developed a homologous rat strain to investigate the pathogenic effect. The ovaries of homozygous (Zp1MT/MT) females possessed both growing and fully grown oocytes; the oocytes completely lacked a ZP, but ZP1 was detectable inside the cytoplasm. Only 1–2 eggs were recovered from oviducts of superovulated Zp1MT/MT females, while an average of 21 eggs were recovered from superovulated Zp1WT/WT per female. The eggs of Zp1MT/MT females were not surrounded by a ZP and lost their fertilization capacity in vitro. Zp1MT/MT females mated with wild-type males failed to become pregnant. Studies in 293T cells showed that mutant Zp1 resulted in a truncated ZP1 protein, which might be intracellularly sequestered and interacted with wild-type ZP3 or ZP4. Our results suggest that the Zp1 point mutation led to infertility and loss of the ZP in oocytes in rats.
Soluble fms-like tyrosine kinase-1 and angiotensin2 target calcitonin gene-related peptide family peptides in maternal vascular smooth muscle cells in pregnancy†
Authors: Chauhan Madhu , Betancourt Ancizar , Balakrishnan Meena , Mishra Akansha , Fox Karin , Belfort Michael , Yallampalli Chandra
Published: February 2021

Calcitonin gene-related peptide (CALCB), adrenomedullin (ADM), and adrenomedullin2 (ADM2) are hypotensive peptides that belong to CALCB family of peptides. Goal of this study was to identify the effect of fms-like tyrosine kinase (sFLT-1) and angiotensin2 (Ang2) on the function of these peptides in OA smooth muscle cells (OASMC) and assess the sensitivity of OA for these peptides in preeclampsia (PE) and normotensive pregnancy. Methods: Peptide function was assessed by Cyclic adenosine monophosphate (cAMP) assays and wire myograph; mRNA expression by Polymerase chain reaction (PCR) and protein-protein interaction by proximity ligation assay and co-immunoprecipitation. Findings: All three peptides increased cAMP synthesis in the order of efficacy CALCB > ADM = ADM2 and vascular endothelial growth factor (VEGF) mRNA in OASMC (P < 0.05); sFLT-1 mediated decrease in cAMP synthesis (P < 0.05) is differentially rescued by all three CALCB family peptides in OASMC (P < 0.005); sFLT-1 decreased receptor activity-modifying protein (RAMP)1 and RAMP2 mRNA expression (P < 0.05); Ang2 decreased the expression of calcitonin-receptor-like receptor and RAMP1 mRNA and desensitized CALCB and ADM2 receptors in OASMC (P < 0.05); sFLT-1 increased RAMP1and Ang2 type 1 receptor (AT1R) interaction in OASMC which is inhibited in presence of all three peptides; and all three peptides relax OA in PE with enhanced ADM2 response (P < 0.05). Conclusion: sFLT-1 and Ang2 impair OASMC mediated functional responses of CALCB family peptides which can be inhibited by respective peptide treatment. The sensitivity of OA for CALCB, ADM, and ADM2-mediated relaxation is retained in PE.
High-fat diet, adipokines and low-grade inflammation are associated with disrupted tendon healing: a systematic review of preclinical studies
Authors: Elli Silvia , Schiaffini Gabriele , Macchi Marina , Spezia Matteo , Chisari Emanuele , Maffulli Nicola
Published: February 2021

Background

The aetiopathogenesis of tendinopathy is uncertain, but inflammation may play a role in the early phase of tendinopathy and in tendon healing response. We investigated the most up-to-date evidence about the association between obesity, high-fat diet and tendinopathy, focusing on the role of adipokines, inflammatory pathways and molecular changes.

Sources of data

A systematic review was performed searching PubMed, Embase and Cochrane Library databases following the PRISMA guidelines. We included studies of any level of evidence published in peer-reviewed journals. The risk of bias (SIRCLE) was assessed, as was the methodological quality (CAMARADES) of the included studies. We excluded all the articles with a high risk of bias and/or low quality after the assessment. After applying the inclusion and exclusion criteria, we included 14 studies of medium or high quality.

Areas of agreement

A high-fat diet negatively affects tendon quality, increasing the risk of rupture and tendinopathy.

Areas of controversy

Controversial evidence exists on both tendon fat infiltration secondary to a dysregulation of the lipid metabolism and of a molecular effect of inflammatory pathways.

Growing points

The secretion of adipokines is strictly related to fat ingestion and body composition and can potentially act on tendon physiology and injury.

Areas timely for developing research

Adipokines, low-grade inflammation and fat intake play a role in disrupting tendon healing and setting up tendinopathy. Further high-quality research is needed to better define the molecular pathways involved.