bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of indigenous yam pounding machine for home use
Authors: Olaleye S A , Arisoyin A G , Omoniyi O , Elemide O A , Okunola A A
Published: March 2020

Pounded yam is a local delicacy rated as special food in Nigeria. It is always prepared using a local means – mortar and pestle. Due to development in technological advancement, the mechanical preparation of pounded yam at home using simple machine is imperative. Several efforts made on home-made devices for this purpose need more research and technology. This paper discussed an indigenous yam pounding machine developed by the Department of Agricultural and Bio-Environmental Engineering, Federal College of Agriculture Akure, Nigeria. It operated with principle of horizontal rotational milling of the yam by beater attached to the pounding chamber. The beater of mass 0.157 kg supplied force of 155 N at 1500 rpm, required for optimum pounding of the fed cooked yam. The maximum load of yam per batch of pounding is 11.9 kg. The machine has power rating of 1 hp while its capacity is 1.07 tons/hr. The testing of the machine revealed it as best operated at 1500 rpm to achieve pounding efficiency of 97%. This makes the machine a good home appliance for safe and effective pounded yam making.
Evaluation of airflow movement within a broiler shed with roof ventilation system during summer
Authors: Jongbo A O , Moorcroft I , White D , Norton T , Okunola A A
Published: March 2020

Indoor conditions of broiler sheds are influenced by environmental parameters such as temperature, relative humidity and air movement. Air temperature and relative humidity contribute mainly to the heat stress in broilers and are controlled by air velocity. Roof ventilated broiler sheds are designed to mechanically force air into a confined space through a negative pressure. They have bottom-hinged inlets and roof fans. In summer, the air inlets of the broiler sheds are usually opened fully, in addition to the mechanical fans in 100% operation to ensure broiler chickens are properly ventilated to prevent heat stress. Surprisingly, no information on the practice of farmers during summer in roof ventilated broiler shed is available. Hence, this work was carried out to assess air movement within a roof ventilated broiler shed during summer. The results of this work indicated that opening the inlets fully during summer may not improve the air movement at the animal microclimate. The average air velocities at the animal microclimate were found to be between 0.30 and 0.40 m s−1 in an empty broiler shed compared to the occupied broiler shed which varied from 0.10 and 0.20 m s−1. Therefore, this work has shown that airflow at the birds’ microclimate inside the broiler shed are mainly influenced by the birds themselves, inlet opening technique and distance from the sidewall.
Effect of different brands of Nigerian cement on the properties of pervious concrete
Authors: Gana A J , Atoyebi O D , Ichagba R B
Published: March 2020

Pervious concrete can be immensely used in the construction of farm structures for irrigation purposes in agriculture. This study evaluated the effects of different brands of Nigerian cement on the properties of pervious concrete. Four different brands of Portland cement; Dangote Falcon(grade 32.5), Elephant Supaset (grade 42.5), Elephant Lafarge (grade 32.5) and Dangote 3*(grade 42.5) were used to produce pervious concrete of mix ratio 1:4 and tests such as compressive strength, permeability and density were tested, the void content was also analyzed. The densities of pervious concrete produced were between 2000 kg/m3
– 1948 kg/m3
, with Elephant Supaset being the densest. All brands produced PC of compressive strength higher than 6 N/mm2
which is the minimum strength requirement in BS 5224 Dangote Falcon cement had the highest compressive strength followed by Elephant Supaset, Elephant Lafarge and Dangote 3* in that order after a 21 day curing period with values 16.39 N/mm2
, 13.97 N/mm2
, 13.54 N/mm2
and 13.11 N/mm2
respectively. Elephant cement PC was most permeable with a 10.1 mm/sec value, followed by Dangote 3* with 9.98 mm/sec then Dangote and Elephant S had 9.89 and 8.46 mm/sec respectively. Density is inversely proportional to porosity and permeability. Elephant Lafarge cement had the highest void content with 20.43% followed by 20.13%, 19.52%, 18.31% respectively for Dangote 3*, Dangote Falcon, Elephant Supaset.
Land snail from limestone karst in Java: an update with notes on their distribution
Authors: Mujiono N , Priawandiputra W
Published: March 2020

Limestone karst in Java is rich of land snail fauna. Unfortunately, the ecosystem is now threatened by mining or tourism activities. However, the impact of that activities on land snail diversity is not well studied. The objective of this study was to inventory the diversity of land snail in limestone karst with focus on their ecological and distribution in Java. Purposive sampling methods using plots (10 x 10 m) were used in 12 different stations in Western Java, Central Java, and Yogyakarta during 2017-2018. Thirty-five species from eleven families of land snail were identified. The highest species richness and population of land snails were found in Watu Blencong (16 species and 158 individuals).Landouria rotatoriadistributed in eight locations, whileJaponia ciliocinctum(85 individuals) distributed in six locations. Results showed that extended distribution records of ten land snail species were reported. Currently, 63 species of land snails species have been identified in karst ecosystem in Java.
Morphometric characteristics and heavy metal bioaccumulation in edible freshwater gastropod (Filopaludina javanica)
Authors: Priawandiputra W , Huda M I N , Kardinan A K , Prawasti T S
Published: March 2020

An edible gastropod, Filopaludina javanica, is widely distributed in freshwater habitats. It was the most abundant gastropod species with variation on size at some lakes in Bogor. However, the relation between morphological size and heavy metal concentration in F. javanica is barely understood although gastropods are well known to accumulate heavy metal. The aim of the research is to measure the impact of concentration of lead (Pb) and cadmium (Cd) concentration to the morphological size of F. javanica in Situ Gede, Bogor. Sampling of the species was carried out in February and April 2017 in Situ Gede (SG), Situ Panjang (SP), Situ Burung (SB) and Situ LSI (SL) while samples for heavy metal accumulation analysis were collected in January and February 2018 in SG. The morphological characteristics of the samples’ shell were measured. Body mass samples were powdered and analyzed using Atomic Absorption Spectrophotometry (AAS). The average range of length and wide shells (mm) were 8.89-30.25 and 7.40-24.80, respectively. The average concentration of Pb and Cd were 0.82 and 0.11 ppm, respectively. The morphometric variability of the species varied among lakes while the concentration of Pb and Cd in this study was generally lower than the acceptable limit.
Exploration of Parmotrema tinctorum and Leptogium sp. lichens as bioindicator of air quality in Mekarsari fruit park
Authors: Safitri R R , Sudirman L I , Koesmaryono Y
Published: March 2020

Lichens are often used as bioindicator to monitor air quality. This study aims to use the Mekarsari Fruit Park area as a model to analyse the population ofParmotrema tinctorumandLeptogium, and considering the possibility of using them as bioindicator of air quality. The method used is descriptive exploratory with survey techniques. The observation plots were consisted of 3 zones, each of 1000 trees. The samples of each plot were identified morphologically and chemically and then the lead contents were determined usingAtomic Absorption Spectrophotometry. Parmotrema tinctorumwere found in all zones butLeptogiumonly found in zone 3. Lead contents ofP. tinctorumthalli in each zone of 1, 2, and 3 were 13.34, 24.87, and 23.61 ppm with the number of total thalli were 8, 223, and 469, the thalli area of 3369. 91 cm2, 39259.48 cm2, and 98984.97 cm2and the average thallus area (ATA) of 1.3, 13.8, and 17.2 cm2.P. tinctorumtends to be tolerant lichen, because the lead content increasing of 43-46% caused increasing of 96-98% thalli number, 91-97% of thalli area, and 91-92% of ATA. AlthoughLeptogiumspp. are known as sensitive lichens, it occurred in higher lead concentration zone.
Newly distribution record of four marine crabs (Decapoda: Brachyura) collected from Seribu Island-Jakarta, Indonesia
Authors: Hanim N , Aditya I , Rini M , Farajallah A , Wardiatno Y
Published: March 2020

Brachyuran is an important biotic component in marine ecosystems, and is known as a keystone species. Information about brachyuran species in Indonesia, in this case from Seribu Islands-Jakarta, is still limited, especially for the non-economic crabs. Based on the manual sampling, it was found that there are four crabs that have not been reported from the Islands, i.e. Ozius guttatus, Carpilius maculatus, Gelasimus hesperiae, and Etisus laevimanus. In term of ecological point of view, the Islands are influenced by the Jakarta Bay as food provider for supporting the live of brachyuran crab. Crab database is necessary to increase the utilization of crabs in the future, e.g. as antibacterial activity and the sources of chitin and chitosan.
How will oil palm expansion affect to butterflies diversity in Jambi, Indonesia?
Authors: Panjaitan R , Buchori D , Peggie D , Harahap I S , Drescher J , Scheu S , Hidayat P
Published: March 2020

The convertion of forest functions to oil palm plantations has an impact on biodiversity. One of the impacts of biodiversity may affect the butterflies diversity. This research was conducted in one of the oil palm areas in PT. Humusindo in Jambi. The purpose of this study were to determine the diversity and active time of butterflies in oil palm plantations of PT. Humusindo Jambi. The study was conducted for 2 months. Sampling method used for this research were scan sampling in the oil palm plantation area by capturing using insect nets. Butterflies are captured using insect nets then counted, marked (to avoid repeated calculations) and released again. Observation separated per one hour starting at 08.00 am to 04.59 pm. The results showed the highest diversity index of butterflies found was at 13.00-13.59 (H’=2.39) with total species number was 34 species. Overall, the butterfly diversity index found was relatively low (H’=1.78) with total species number was 54 species. The most dominant butterfly species found at each time of observation was Yptima praenubila. The conservation status of all species found were common species (there is no endemic species) and least concern in the conservation status.
Isolation and identification of lactic acid bacteria in hive of Apis dorsata from semi-arid tropical climate in Benu village, East Nusa Tenggara
Authors: Karyawati A T , Nuraida L , Lestari Y , Meryandini A
Published: March 2020

Lactic Acid Bacteria (LAB) have been isolated from the hive of Giant Honey Bee (Apis dorsata) origin from tropical climate. Information about the diversity of LAB from the hive of A. dorsata from Benu Village has not been found yet. The information is important as a preliminary study of the potential of biological resources for food functional development in the future. Therefore, it is needed to research on diversity of LAB that isolated from the hive of A. dorsata from the village of Benu as an area of semi-arid tropical climate. The purpose of this study is determine the diversity of LAB isolated from the hive of A. dorsata from Benu Village. This research is important because it provides preliminary information about the diversity of LAB species from the hive of A. dorsata from Benu Village as a representation of semi-arid tropical climate. Profile of Denaturing Gradient Gel Electrophoresis showed the presence of seven LAB isolates from the hive of A. dorsata in Benu Village. This is an early indication that hive of A. dorsata from semi-arid tropic climate has the potential as a biological resources of LAB that important for food funtional development in the future.
Seed exploration and conservation in Ciremai Mountain National Park and Kerinci Seblat National Park
Authors: Wanda I F , Oksari A A , Sahromi  , Mimin  , latifah D
Published: March 2020

Seed storage at a seed bank facility is one of the ex-situ bioresources conservation strategies in the world’s Botanical Gardens. Enrichment of species for seed banks is done through exploration in various forest areas. The exploration and conservation of seeds have been done in Ciremai Mountain National Park (CMNP) on November 7-16th, 2016 and Kerinci Seblat National Park (KSNP) on April 11-20th, 2017. This research aims to search and collect plant seeds and to know the diversity of species from fruiting plants and seeds. Furthermore, this exploration also aims to study a biological seed that support conservation efforts for these plants. Research used an exploratory method at each location. The recording of ecological data includes habitat, altitude, soil pH, soil moisture, and air temperature. This study obtained thirty-two (32) collection numbers in the CMNP area consisted of 20 families and 28 genera; and thirty-three (33) collection numbers consisted of 21 families and 31 genera in the KSNP area. Most of the seeds found are orthodox seeds that can be stored for a relatively long time.
Biological synthesis and characterization of silver nanoparticles synthesized from Pometia pinnata and Diospyros discolor Fruits
Authors: Handayani W , Nolia I , Sundari R M , Imawan C
Published: March 2020

The use of biological agents for nanoparticle biosynthesis is an alternative to the eco-friendly green synthetic method. In this study, fruit extracts from Pometia pinnata (Matoa) and Diospyros discolor (Bisbul) were used as reducing agents to produce silver nanoparticles (AgNPs). The ratio of silver precursors to water extracts from the fruit and the reaction time was observed to determine optimum reaction conditions. The characterizations were carried out using a UV-Vis spectrophotometer, Transmission Electron Microscope (TEM), and Particle Size Analyzer (PSA) to analyze the size and morphology of the AgNPs. With the increase in the volume ratio of extracts and silver nitrate, the absorption peak intensity tended to increase—these results were shown by the color of the colloid. Based on the comparison of these two extracts, the peak absorbance of the synthesis using D. discolor fruit extract was higher than P. pinnata. The result showed D. discolor fruit extracts had faster reaction times for AgNPs synthesis. The average size of silver nanoparticles from D. discolor was 32 nm and from P. pinnata was 51 nm. The use of D. discolor fruit extract tends to produce smaller AgNPs. This method can be developed for further application for antimicrobial nanoparticles and sensors.
The characteristic of stingless bee’s products (Tetragonula spp.) in Lombok Island
Authors: Wahyuni N , Anggadhania L
Published: March 2020

Beekeeping is one of the excellent businesses for people around the forest. To date, the bee species that began to broaden are stingless bees. Tetragonula spp. is a stingless bee species in Lombok that have been promoted. This research aim is to determine the characteristic of stingless beekeeping products in Lombok. The meliponiculture products of Tetragonula spp. consist of honey, beebread, and propolis. SNI 3545 was used to examine the honey characteristic of Tetragonula spp., the proximate analysis was performed for beebread products and phytochemical analysis was used to stingless bee propolis products. The results showed that stingless bee honey has a value that fulfills 65% standard, the diastase enzyme was <3 DN and acidity was < 200 ml NaOH/kg. The average content of moisture, ash, protein, fat, and carbohydrates from bee bread were 24, 2, 15, 9.5, and 49% respectively. The phytochemical analysis results of propolis determined that all samples contain flavonoids, tannins, saponins. Several of them positively steroid detected. This study results could be used to considerate further research related in manufactured final products of stingless bee products as raw materials.
Growth and yield of five Indonesian new superior varieties of soybean in dry climate rainfed rice fields
Authors: Aisah A R , Herawati N , Hidayah B N
Published: March 2020

Indonesian new superior varieties of soybean are continually released as an effort to increase soybean productivity. Some new superior varieties such as Devon 1, Dena 1, and Dega 1 were not widely known by the stakeholders. This research aims were to investigated the growth and yield of five Indonesian new superior varieties of soybean in the dry climate rice field. The experiment was conducted from March to July 2018 in Segala Anyar Village of Central Lombok Regency, West Nusa Tenggara Province, Indonesia. The experimental design was used non-factorial randomized block design with the soybean varieties as treatments (Devon 1, Dena 1, Anjasmoro, Argomulyo, and Dega 1). Each treatment was repeated four times. The parameters observed included plant height, number of branches, number of leaves, number of sections, number of pods, and soybean production. Data were collected from 10 crop samples for each replication during vegetative phase 1 and 2. The results showed that the soybean varieties had a significant effect on plant height, number of branches, number of sections and production. The crop could not produce optimally during field experiment due to lack of water in the pod-filling phase. Generally, it could grow well and has ability to produce yield.
Oxygen consumption of barred loach Nemacheilus fasciatus (Valenciennes, 1846) on different temperatures
Authors: Prakoso V A , Kurniawan
Published: March 2020

This study aims to investigate the effects of temperature regimes on oxygen consumption of barred loach Nemacheilus fasciatus. Three experimental groups were set to measure oxygen consumption (OC) of the rearing fish (Length: 6.14 ± 0.4 cm; Weight: 1.46 ± 0.05 g) on different temperatures (21.5, 26.5, and 31.5°C) with six replicates. Fish were adapted in an aquarium before stocked and observed in a closed respirometer system (Stocking density: 10 fish/L; Respirometer volume: 1.4 L). Barred loach consumed 365.9, 320.9, and 298.4 mg O2/kg/h at 21.5, 26.5, and 31.5°C indicating that the OC decreased gradually with increasing water temperature. However, oxygen consumption of barred loach did not change significantly within the temperature range from 21.5 to 31.5°C. The ventilation rate of barred loach increased from 115.0 ± 8.9 to 265.2 ± 42.5 times/min between 21.5 and 31.5°C. Oxygen consumption per breath of barred loach was higher at a lower temperature (3.18 ± 0.63, 2.11 ± 1.22, and 1.13 ± 0.57 mg O2/kg/breath at 21.5, 26.5, and 31.5°C) (P<0.05). In terms of Q10, the lowest value was found between 26.5 – 31.5°C with a value of 1.16. The thermal range was a comfort zone for barred loach to maintain their metabolic efficiency.
Immunocapture reverse transcription polymerase chain reaction for detection of sugarcane streak mosaic virus
Authors: Subekti D , Hidayat S H , Damayanti T A , Purwono
Published: March 2020

Detection of plant viruses can be done by protein or nucleic acid approaches. The immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) method is a combination of the two approaches. Research was carried out to develop and validate IC-RT- PCR based-detection method for SCSMV, which can be applied for the sugarcane seed indexing program to support the national government’s goal for sugar self-sufficiency. Evaluation of the IC-RT-PCR method was conducted using 5 field samples. Conventional PCR and serological methods, i.e. dot immunobinding assay (DIBA) and enzyme-linked immunosorbent assay (ELISA) was also performed in the same time. All field samples gave a positive reaction to SCSMV antibodies in the DIBA and ELISA methods with the intensity of the reaction varying from low to high. SCSMV was still detected on plant extract up to 104 dilution by ELISA and DIBA. Specific DNA fragments were successfully amplified from 2 field samples using the conventional PCR method; whereas the IC-RT-PCR method was successfully amplified all field samples. Optimization test showed that the IC-RT-PCR method was able to detect SCSMV from plant extract up to 10−10 dilutions. IC-RT-PCR method is more sensitive than conventional PCR and might be recommended for the indexing method to produce high-quality virus-free sugarcane seed.
Analysis of DNA methylation and its correlation with mRNA expression of epidermal growth factor receptor encoding for cytoskeleton regulating protein in peritoneal endometriosis tissue
Authors: Zahrah A , Muharam R , Marwali M L S , Sururi A , Harzif A K , Pratama G , Ocktariyana  , Asmarinah
Published: March 2020

It has been known that the EGFR have the role for regulation the cytoskeleton activity and its expression increased in endometriosis tissue. The aim of this study was to evaluate the DNA methylation of the EGFR gene that might cause the alteration of its mRNA expression in peritoneal endometriosis tissue. Samples were peritoneal endometriosis tissue from 20 endometriosis patients and 20 female of non-endometriosis patients. The DNA methylation of the EGFR gene was analyzed by the method of Methylation Specific PCR and ImageJ software, while its expression of mRNA were analyzed by the method of qRT-PCR. The DNA methylation in the EGFR gene in peritoneal endometriosis tissues increased compared to normal endometrial tissues (peritoneal endometriosis tissue = 56%, normal endometriosis tissue = 19%). The expression of mRNA EGFR gene in endometriosis peritoneal tissues was 1.341 fold increased relative to normal endometrium. There is no significant correlation between the DNA methylation with expression of mRNA EGFR (p = 0.947 and r = -0.016). Increasing of EGFR mRNA expression in endometriosis tissue that was not caused by alteration of its DNA methylation, have to play a role in the pathogenesis of endometriosis.
Callus response of hybrid and Madura local corn to salt stress
Authors: Sukma K P W , Daryono B S , Purnomo  , Suprapti I
Published: March 2020

Salinity (salty and acidity) is one of important abiotic stresses, which can decrease corn production. In Indonesia, corn is one of important cereal crop beside rice. Madura is an island that known as widest area of maize landfill in East Java but has lowest productivity. Madura local corns (var. Manding, Duko and Elos) and hybrid corn (var. Sukmaraga) known as salt tolerance. This research objectives was to compare response of those callus to salt stress. Callus responses to salt stress, can indicate to their resistance to salinity. The young corn stalks were induced to be callus by MS+2,4D 4mg/L, then cultivated to media MS+NaCl (0, 100, 200 mM) for 30 days. The parameters were morphology (colour and texture), survived and proline content. Proline content was measured by nynhidrin methods. The results showed that salt stress change callus colour (from white to creamy white and brown) and texture (from friable to compact and intermediate). Duko and Elos survived more than 90%, but Manding and Sukmaraga survived less than 15%. Salt treatment increased proline content of all callus. Madura local corn had better tolerance to salt stress than hybrid.
Phylogenetic relationships among Indonesian wood borer pests, xyleutes, and its allied genera (Lepidoptera: Cossidae)
Authors: Fitriana Y S , Darmawan  , Wiyati S Y , Sutrisno H
Published: March 2020

Xyleutes and its allied genera are two of the major wood borer pests in South East Asia, especially in Indonesia. The systematics of this group is still vague since all these genera were mostly described based on superficial external characters only. Therefore, the validity of each genus within this group needs to be assessed based on more comprehensive data. To assess the monophyly of each genus, and to elucidate the relationship of the Indonesian Xyleutes and its allied genera, we analyzed 28 species from 11 genera based on nucleotide sequence variation across a 579-bp region in the CO I gene. The results showed that ML tree- building methods recovered almost all sections recognized based on morphological characters. Some genera such as Morpheis, Chalcidica, and Rapdalus are valid genera and their relationship within each genus well resolved. On the other hand, genera Trimoslemos, Zeuzera, and Xyleutes seem to be paraphyletic groups. Those genera, indeed, need revision based on materials not only from Indonesia but also from other countries. The current phylogeny proposed here is necessary to be evaluated by involving conserved genes to get better resolution for the relation among all genera.
Temperature Effect on Dielectric and AC Breakdown Properties of the Cellulose Insulation Paper Immersed in Mineral-Palm Oil Mixture
Authors: Zhu Mengzhao , Zhu Wenbing , Chen Xin
Published: March 2020

Mixed oil is considered as an ideal insulating fluid for its great physicochemical and insulation properties. A novel mixed oil consisted of 75 vol.% mineral oil and 25 vol.% palm oil, was developed by our team and its main properties basically come up the standards of IEC 60296:2012. In this study, the dielectric properties of mineral oil-impregnated paper (MIN-IP) and mixed oil-impregnated paper (MIX-IP), were comparative analyzed at 25 °C-65 °C, including relative permittivity and dielectric loss factor. The temperature effect on AC breakdown properties for MIN-IP and MIX-IP were also researched at 25 °C-75 °C. The result shows that MIX-IP have higher relative permittivity and dielectric loss factor than MIN-IP. The difference on dielectric strength between MIN-IP and MIX-IP is more significant at 45 °C to 65 °C.
Effect of SLM Process Parameters on Relative Density of Maraging Steel (18Ni-300) Formed Parts
Authors: Huang Weidong , Zhang Weijie , Chen Xiayu
Published: March 2020

Taking maraging steel (18Ni300) powder as the research object, the influence of the density of forming parts such as laser power p, scanning speed v, scanning spacing s and powder thickness h during the rapid forming process of SLM laser was studied by orthogonal test. The experimental results show that the laser power and scanning spacing have a significant effect on the density of the molded part, while the powder thickness and scanning speed have no significant effect on the relative density of the molded part. The order of importance of the influence of each factor on the compactness of the formed part is the laser power, the scanning spacing, the scanning speed, and the powder thickness. The best combination of process parameters is a laser power of 260 W, a scanning speed of 700 mm/s, a scanning spacing of 0.11 mm, and a powder thickness of 0.02 mm. When the laser volume energy density is between 70 J/mm3 and 185 J/mm3, the relative density can reach more than 99%, and it can increase to 99.99% during this interval.
Predicting Mechanical Properties and Corrosion Resistance of Heat-Treated 7N01 Aluminum Alloy by Machine Learning Methods
Authors: Cao Xinyu , Zhang Yingbo , Chen Hui
Published: March 2020

In this paper, mechanical properties and corrosion resistance of different heat-treated 7N01 aluminum alloys are measured. A novel approach is proposed to establish the relationship between heat-treated processing parameters and the properties using machine learning methods. With a set of trustable data, generalized regression neural network (GRNN), support vector machine (SVM) and multiple linear regression (MLR) are applied in the prediction of mechanical properties, while GRNN and SVM, two prevalent machine learning methods, are also employed to predict the corrosion resistance. By comparing coefficient of determination (R2) and mean absolute percentage error (MAPE), we demonstrate, GRNN and SVM are indeed useful machine leaning methods for both modeling and predicting. In virtue of the new approach, we can also establish other goal-oriented models for design and prediction as long as the training data set is available. Finally, it’s found that both single-stage aging and retrogression re-aging can make the alloy reach higher strength values than double-stage aging, however the corrosion resistance of double-stage aging alloy is better than that of single-stage aging.
Fabrication of Crosslinked Waterborne Polyurethane with Low-Gloss and Micro Roughness for Matting Application
Authors: Yong Qiwen , Yang Yuzi , Wei Daidong
Published: March 2020

A groups of cross-linked waterborne polyurethane (CPU) coatings were successfully synthesized and characterized. The CPU emulsions could achieve low gloss effect without addition of any matting agents by the formation of self-roughed surface. Rheological research shows that the emulsions comply with the Herschel-bulkley pseudoplastic fluid model with a yield stress, and exhibited the same behaviors as the gel. SEM and AFM illustrated the rough surface morphology of the films, and a series of roughness parameters were calculated. In general, the resulted CPU emulsions can provide moderate roughness levels, good hardness and adhesive strengths after film-forming, which were very appropriate for use as matt coating.
Using DSC Studying the Relationship between Water Absorbency of Superabsorbent Polymer and Its Structure
Authors: Jiang Zuming
Published: March 2020

A series of superabsorbent ter-polymers (SAPs) with acrylic acid, acrylamide and 2-acrylamido-2-methylpropanesulfonic acid, crosslinked by polyethyleneglycol diacrylate-600 were prepared. The SAPs were characterized by Fourier transform infrared spectra (FTIR) and the water absorbency was measured by the Tea-bag method. Differential scanning calorimetry (DSC) was used to determine the bound water content of the different samples with various water contents. It was found that the more hydrophilic groups the ter-polymer has, the larger the bound water content is, the stronger the ability of interacting with water is, and the larger the water absorbency the ter-polymer has.
Preparation and Comparison Anticorrosive Properties of Graphene Anticorrosive Coatings
Authors: Chen Qiang , Zhao Yue-Ju , Teng Ji-Lin , Xia Yi-Qin , Yu Bao-Qin , Zheng Yongli
Published: March 2020

Since graphene was successfully stripped from graphite in 2004, its excellent properties and unique two-dimensional layered structure have attracted great interest in the field of coatings. Graphene can be used as a filler in anticorrosive coatings. Its good electrical conductivity and sheet-like barrier properties which can isolate oxygen and corrosive media. So, graphene powders can improve the corrosion resistance of the coating. With the development of the industrialization of graphene, which made the production cost of graphene is gradually reduced, it made graphene can be used in coatings be possible. This article introduces a method for preparing graphene heavy-duty anticorrosive coating, the anticorrosive principle of graphene heavy anticorrosive coating was described. The salt spray resistance of graphene heavy anticorrosive coatings and international brand heavy anticorrosive coatings were compared.
Out-of-Pile Performances of Zr-Sn-Nb-Fe Alloys for PWR Fuel Cladding
Authors: Zhuo H , Yang Z B , Cheng Z Q , Yang Y F , Zhao W J
Published: March 2020

The safety and reliability of Pressure Water Reactors (PWRs) is closely related to the performances of zirconium (Zr) alloy as fuel rod cladding material. Zr-Sn-Nb-Fe series alloys are one of the important directions for continuous improvement of zirconium alloys for high burn-up fuel element claddings. Two new zirconium alloys, N1(Zr-0.5Sn-0.15Nb-0.5Fe-0.25V) and N2(Zr-0.2Sn-1.3Nb-0.1Fe-0.05V) have been developed to use as advanced PWR fuel rod cladding materials through the studies of the corrosion behavior of Zr-Sn-Nb-Fe Alloys, the composition optimization, the preparation of claddings and the out-of-pile performances and in-pile tests of new zirconium alloys. The results are obtained by out-of-pile performance tests of two Zr alloy claddings. Transmission Electron Microscopy (TEM) results shown that fine and uniform distribution of β-Nb and/or ZrFeV(Nb) particles could lead to excellent out-of-pile corrosion resistance. Autoclave testing in 360 °C/18.6 MPa pure water, 60 °C/18.6 MPa/70 ppm Li+ aqueous solution and 360 °C/18.6 MPa/1000 ppm B3+/3.5 ppm Li+ aqueous solution indicated that both of N1 and N2 alloys possessed better corrosion resistance than Zr-4 alloy. The hydrogen uptake results of two kinds of alloys from corrosion reactions under various corrosion conditions showed hydrogen uptake increased with the exposure time or oxide thickness, and hydrogen uptake rate of the new alloys after long-term corrosion are lower than Zr-4. Moreover, the new alloys have demonstrated superior or similar out-of-pile tensile, burst and creep properties relative to Zr-4.
Effect of Doping Radio on Thermoelectric Properties of Na1-xAgxCO2O4
Authors: Luo Xiaodong , Wang Hong , Zhang Liping , Li Xinliang , Luo Qiang , Yi Junlin
Published: March 2020

Oxide thermoelectric materials have the characteristics of simple conversion device structure and no environmental pollution. In this paper, a series of Na1-xAgxCO2O4 thermoelectric materials with different doping radios were prepared by sol-gel synthesis method and microwave sintering method. Through the analysis of XRD, Seebeck coefficient, thermal conductivity and conductivity, the best effect is the doping ratio 0.3. To certain extent, the ZT value of the material is increased, and the relationship between nano scale and thermoelectric performance is obtained, which provides a new method for the preparation of thermoelectric materials.
Determining the Activation Energy of Solid-State Phase Transformation of 1035 Steel from Isoconversional Analysis of DSC Data
Authors: Tan G L , Tang D , Mu T , Li Z , Xu J X , Wang X M
Published: March 2020

The results of solid-state phase transformation kinetics analysis for the steel have been controverted because of the complexity and diversity. In this paper, the activation energy, which represents the energy barrier for austenite to pearlite solid-state phase transformation of 1035 steel, was determined from the nonlinear isoconversional method. The result shown that the activation energy is change with the degree of transformation. Therefore, the nonlinear isoconversional approach maybe a better way to calculate the activation energy of solid-state phase transformation.
Effects of Thickness and Pre-stretching Ratio on Quenching Residual Stress in 7050 Aluminum Alloy Thick Plate
Authors: Cao H L , Wang J Q , Liu C , Niu G M
Published: March 2020

The quenching residual stress in 7050 aluminum alloy thick plate was simulated by using the finite element method (FEM). And the FEM model was verified the experimental results. Then the effects of thickness and pre-stretching ratio on quenching residual stress were studied using the FEM model. The simulation results showed that the quenching residual stress increases gradually with the increase of thickness. The residual stress increased rapidly with the increase of thickness when the thickness between 40mm and 80mm. While the residual stress increased slowly when the thickness exceeds 80mm. The quenching residual stress decreased gradually with the increase of pre-stretching, but the decreasing extent slowed down gradually. When the pre-stretching amount exceeded 2.5%, the reduction ratio can be achieved more than 95.0%. Considering the efficiency of the reduction of quenching residual stress as well as the economy, the pre-stretching ratio should be set between 2.5% and 3.5%.
Effect of In-Situ Reinforced Particle on the Failure of TiC/AZ91 Composites
Authors: Shao Letian , Yao Junping
Published: March 2020

By using image processing, recognition technology and edge extraction technology, the true particle morphology and distribution of TiC / AZ91 composites were obtained, and finite element numerical calculation models of different particle shapes were established. with the help of ansys finite element software, the stress distribution and maximum strain values of TiC/AZ91 composite under different enhanced particle shapes are studied to explore the influence law and mechanism of the material on the failure behavior of the material. The results show that, compared with round particles, square particles are prone to plastic damage and lead to the destruction of magnesium-based composites.
Reaction Mechanism Analysis of Phosphorus Slag - Fly Ash - Phosphorus Gypsum - Cement Foamed Concrete
Authors: Liu Qiumei , Li Caiyu
Published: March 2020

In this study, phosphorous slag powder, fly ash and cement were used as composite cementing materials, and phosphogypsum was used as the activator of phosphorous slag powder and fly ash to stimulate their activity. The hydration reaction of cement, phosphorus slag powder, fly ash and phosphogypsum was studied. The results show that the hydration products of cement, cement + phosphorous slag powder, cement + phosphorous slag powder + fly ash, and cement + phosphorous slag powder + fly ash + phosphorous gypsum have the same mineral composition but different relative content. The hydration samples of cement, cement + phosphorous slag powder, cement + phosphorous slag powder + fly ash, and cement + phosphorous slag powder + fly ash + phosphogypsum have certain differences in microstructure and quantity, especially ettringite. Cement hydration can stimulate the activity of phosphorus slag powder and fly ash, in turn, the addition of phosphorus slag powder, fly ash and phosphogypsum can promote the hydration process of cement, improve the quality of hydration products, and improve the density of concrete structure.
Fabrication of Green Concrete by Using Recycled Construction Waste
Authors: Zhao Jian , Gao Peiwei , Yang Zhengxun
Published: March 2020

To fabricate a new green building material without higher CO2 emission and much energy consumption, recycled construction waste was used as a raw material. Metakaolin was introduced as a cementitious binder instead of traditional Portland cement. NaOH and water glass mixture solution played a role of alkaline activator, then the activity of metakaolin would be released to show an excellent performance. The content of metakaolin was varied to obtain an optimal mechanical property and cost ratio. The specimens were fabricated in room, then cured in air after demoulding, robustness properties were measured which consist of compressive strength and bending strength, and their microstructures were investigated finally.
Study on Mechanical and Crack Resistance of Expanded Fiber Reinforced Concrete
Authors: Tian Minghao , Gao Peiwei , Wang Limin , Tian Yilang
Published: March 2020

In order to effectively improve the mechanical properties, deformation properties and crack resistance of concrete, and to control the cracking of concrete, high crack resistance concrete with excellent comprehensive performance is prepared. The basalt fiber and calcium magnesium expansion agent are mixed into the concrete to increase the tensile strength and limit the shrinkage deformation. Starting from the fundamental factors of concrete cracking, control the cracking of concrete and improve its crack resistance. The effects of different basalt fiber (BF) and calcium magnesium expansion agent (EA) and different w/c on the mechanical and crack resistance of concrete were investigated. Three-factor and three-level orthogonal tests were carried out to research the compressive, tensile, flexural, free deformation tests of expanded fiber concrete, at the same time, the best mix ratio was determined. Finally, the SEM test was carried out to analyze the mechanism of crack resistance improvement from the microstructure. The results show that when the fiber content is 1% and the expansion agent is 7%, the concrete has the best crack resistance and the performance improvement effect.
Study on Welding Process of 7×0.5 Multilayer 304 Bellows and Flange
Authors: Jiang Zhaodong , Liang Dong , Zhou Tong , Tong Linlin
Published: March 2020

In order to ensure the welding quality of 7 layers of 0.5-thk 304L bellows and flange, the welding process was studied, and the evolution rules of weld zone forming, mechanical properties and microstructure under four different process conditions are analyzed to determine the best welding process. The results show that the four kinds of welding conditions can obtain the welded joint with good appearance, but the macro fracture analysis shows that for the welding of 7x0.5 bellows, 2mm double-layer welding is the best welding method. At this time, the distance between the outer wall of the bellows and the inner wall of the flange is the smallest, and the penetration is the largest; For the combination welding method of seam welding and fusion welding, the hardness of the seam welding area is the highest, followed by that of the fusion welding area, because the seam welding area is mainly small equiaxed distance, while the fusion welding is mainly coarse columnar crystal.
Study on the Shrinkage Behavior of the Cement Mortar with the Additives of the Nano-Kaolinite Clay
Authors: Fan Y F , Li Q C , Zhang S Y , Luan H Y
Published: March 2020

The effect of nano-kaolinite clay (NKC) on the early age cracking behavior of cement mortar was investigated. The restrained ring-test method was used to detect shrinkage crack tendency of cement mortar specimen. The cracking and strain on the surface of mortar ring for the ordinary and NKC mortar were monitored. The development of crack width and strain during the drying process were obtained. Finite element analysis is carried out to simulate the evolution of the crack in restrained concrete rings subject to circumferential drying. The results demonstrate that the addition of NKC increases the shrinkage cracking tendency of mortar at early age. It is found that the crack width is significantly increased in the mortar specimen added with 3% NKC replacement.
First Principle Calculation of Electronic Structure and Stabilities of TiC/Mg Composites Interfaces
Authors: Xiao Jiangbo , Yao Junping
Published: March 2020

The Millken charge of atom, charge density difference and electronic structures of TiC(111)/Mg(0001) with different stacking sequences were studied by the basis of the first-principles calculation method, and the Interfacial wettability and bond strength were evaluated by interfacial adhesion work. The results show that the C-CS(center site)-Mg interface, the CTS(top site)-Mg interface and Ti-CS-Mg interface is almost no change and the Ti-TS-Mg interface changes into a new Ti-CS-Mg interface after geometry optimization. Compared with the original Ti-CS-Mg interface, the new Ti-CS-Mg interface has a similar ideal work of adhesion and interfacial distance. And the C-CS-Mg interface is the most stable owing to it has the greatest ideal work of adhesion (7.221 J/m2) and the smallest interfacial distance (1.39 Å). The C-CS-Mg and C-TS-Mg interfaces have both covalent bonds and ionic bonds. However, the Ti-CS-Mg interface only has metallic bond.
Reliability Analysis of Clamp Welding Defects Based on Finite Element Simulation
Authors: You Yi , He Cheng , Wang Xinxin , Zhang Ling , Wang Yanzhe , Hu Yibo , Wei Yanding
Published: March 2020

Cracking and failure of clamp is a common problem in the maintenance of power grid, which seriously threatens the safety of power grid electrical transmission. Therefore, based on the finite element analysis method, the static strength check and reliability analysis are firstly carried out to evaluate the structural safety of the defect-free clamp. Secondly, SINTAP was used to evaluate clamps with planar defects, and Paris formula was used to predict the fatigue crack growth life. The results show that the clamp with planar welding defects can also meet the requirements under severe working conditions due to its good plastic reserve and toughness. The crack depth a of the welding defect significantly affects the safety of the clamp structure, and the crack feature a/c also has a certain impact on the safety. However, when the crack depth a is less than a certain value, no fatigue fracture will occur.
Biological and Physical Properties of a Modification Silicone Liner
Authors: Gu Huiru , Luan Huiqin , Mo Zhongjun , Song iang , Fan Yubo
Published: March 2020

Silicone liners provide comfortability for amputees, meanwhile effectively protecting their skin surface and subcutaneous tissue. Silicone liners used in prosthetics are mainly used for filling, cushioning, and suspending a receiving cavity. At present, biological and mechanical properties of silicone liners in prosthetic cavity remain unclear, and the price is expensive for amputees. We improve the silicone material preparation process to reduce the price as well as to ensure the mechanics and biosafety of the material. Characterization of silicone liner surface, cellular toxicity of silicone liner, bacterial adhesion on the surface of silicone liner, and mechanical properties were evaluated and compared among commercial materials (sample A and B) and our improved silicone liner material (sample C). The water contact, the macroscopic surface and the calculated mechanical parameters have no significant differences among the three types samples. The extract of three types silicone liner have no cytotoxicity reactivity. Samples C markedly reduced the adhesion of E. coli compared with sample A. The improved silicone material preparation process ensured the biological and mechanical properties and reduced the price of these silicone liners, thereby increasing their potential as silicone liners of prosthetics cavity.
TiO2/Cu Composite NPs Coated Polyester Fabric for the Enhancement of Antibacterial Durability
Authors: Salvia Binte Touhid S , Shawon Md. Rashidul Kabir , Ali Khoso Nazakat , Xu Qingbo , Pan Dopan , Liu Xiangdong
Published: March 2020

Copper nanoparticles (Cu NPs) were synthesized on a plasma treated polyester fabric having a coating of TiO2 NPs. The fabric was treated with cold O2 plasma first to enhance the surface affinity for TiO2 NPs, then coated with TiO2 NPs via a heat pressing, and finally synthesize Cu NPs on the complex surface using a dip-coating process. The resulting fabric shows an excellent antibacterial effect and outstanding laundering durability, as it has satisfactory bacterial reduction performance against S. aureus and E. coli higher than 98% and behaves stable even after 50 washing cycles. This methodology for preparing antibacterial polyester fabric maybe of high potential applications in cosmetic and medical textiles.
Study on Influence of Dispersants on Stability, Thermal Conductivity and Viscosity of BN/EG Nanofluids
Authors: Li Yanjiao , Qin Zhongbao , Zou Zijie , Hou Li’an
Published: March 2020

Boron nitride/ethylene alcohol (BN/EG) nanofluids was synthesized by two-step method. The influence of dispersant on stability, thermal conductivity and viscosity was studied. The experimental results reveal that the stability of BN/EG nanofluids deteriorates rapidly with the addition of anionic dispersants and cationic dispersants, which has no practical application value. While, non-ionic dispersant can improve the stability and fluidity obviously and maintain the enhancement of thermal conductivity at the same time.
Study the Mechanisms of Enhanced Phonon Bottleneck Effect for the Absorber of Hot Carrier Solar Cell in III-V Multiple Quantum Wells
Authors: Zhang Yi , Huang Chao
Published: March 2020

The most vital key to realize hot carrier solar cell is reducing carrier relaxation time to nanoseconds by phonon bottleneck effect often observed in nanostructure. However, the mechanisms underlying this are still not well understood. In this paper, we systematically investigated the mechanisms of phonon interfacial mismatch and carrier quantum confinement over phonon bottleneck effect in InN/InxGa(1-x)N multiple quantum wells (MQWs). Highly promising hot carrier lifetimes due to enhanced phonon bottleneck effect were observed in these MQWs, where the longest hot carrier lifetime is 3.2±0.12 ns. It was found the quantum confinement of carriers could play more important role in the reduction of carrier cooling rate, while the optical phonon confinement is more likely to dominate the initial carrier temperature. This study clarifies two of the most important mechanisms of phonon bottleneck effect and directs a promising application of III-V MQWs on the absorber of hot carrier solar cell.