Ratio Of Total Length Research Articles

Influence of Scallops on Windage Loss and Flow Characteristics in Disk-Type Gap

Abstract Windage loss and flow characteristics in a disk-type gap featuring scalloped structures are investigated in this paper. Special attention is paid to the size of the scallops and the associated loss models. The respective losses and scallop effects in the gap are explored with various combinations of depths, quantities, and rotating speeds. The results indicate that scallop structures positively contribute to increased windage losses, accounting for more than 60% of the overall losses. An internal spiral vortex band is formed along the scallop wall, with the scallop depth ratio exerting influences on loss, reaching a maximum of 8.1%. The current scallop loss model overlooks the consideration of the total arc length ratio of scallops to the circumference, presenting a limitation, and the maximum relative deviation from numerical simulation results is observed to be 111.4%. An increase in arc length ratio results in a higher total loss, although the loss per individual scallop is diminished, manifesting in reduced vortices and pressure differences. Furthermore, a modified model is proposed to increase the precision of the current loss model. The maximal relative deviations of 13.8% confirm that the modified model is accepted to predict the windage loss in disk-type gaps with scallops. The conclusions offer valuable insights into the structural design of impellers and high-speed electrical machines with superior efficiency.

Evaluating physical controls on conduit flow contribution to spring discharge

The physical controls on the contribution of conduit to spring discharge, quantified as the ratio of conduit flow to spring discharge (Qc/Q), are evaluated through numerical simulations using MODFLOW-Conduit Flow Process. The controlling factors include the ratio of conduit surface roughness to conduit diameter (ε/D), the hydraulic conductivity ratio between the conduit wall and the porous matrix (Kc/K), the ratio of groundwater recharge to the hydraulic conductivity of the porous matrix, and conduit density (Cd) defined as the ratio of total conduit length to springshed area. For a single conduit, Qc/Q increases with Kc/K when flow in the conduit is laminar. When flow is turbulent, Qc/Q is stable and then decreases with ε/D, increases with Kc/K, and decreases with R/K due to the limited exchange capacity between matrix and conduit (i.e., small Kc/K). The results of hypothetical conduit networks show that Qc/Q increases with Cd but is not sensitive to the two sets of network structure evaluated. The sensitivity analysis for the Silver Springs in Florida shows that the spatial heterogeneity of conduit diameter causes higher Qc/Q, and Qc/Q is most sensitive to the conduit density, followed by R/K, and then Kc/K.

Multi-segmental heating of facing vertical walls in porous systems filled with hybrid nanofluid in a constant-strength magnetic environment

PurposeThis study aims to undertake a comprehensive examination of heat transfer by convection in porous systems with top and bottom walls insulated and differently heated vertical walls under a magnetic field. For a specific nanofluid, the study aims to bring out the effects of different segmental heating arrangements.Design/methodology/approachAn existing in-house code based on the finite volume method has provided the numerical solution of the coupled nondimensional transport equations. Following a validation study, different explorations include the variations of Darcy–Rayleigh number (Ram = 10–104), Darcy number (Da = 10–5–10–1) segmented arrangements of heaters of identical total length, porosity index (ε = 0.1–1) and aspect ratio of the cavity (AR = 0.25–2) under Hartmann number (Ha = 10–70) and volume fraction of φ = 0.1% for the nanoparticles. In the analysis, there are major roles of the streamlines, isotherms and heatlines on the vertical mid-plane of the cavity and the profiles of the flow velocity and temperature on the central line of the section.FindingsThe finding of a monotonic rise in the heat transfer rate with an increase in Ram from 10 to 104 has prompted a further comparison of the rate at Ram equal to 104 with the total length of the heaters kept constant in all the cases. With respect to uniform heating of one entire wall, the study reveals a significant advantage of 246% rate enhancement from two equal heater segments placed centrally on opposite walls. This rate has emerged higher by 82% and 249%, respectively, with both the segments placed at the top and one at the bottom and one at the top. An increase in the number of centrally arranged heaters on each wall from one to five has yielded 286% rate enhancement. Changes in the ratio of the cavity height-to-length from 1.0 to 0.2 and 2 cause the rate to decrease by 50% and increase by 21%, respectively.Research limitations/implicationsFurther research with additional parameters, geometries and configurations will consolidate the understanding. Experimental validation can complement the numerical simulations presented in this study.Originality/valueThis research contributes to the field by integrating segmented heating, magnetic fields and hybrid nanofluid in a porous flow domain, addressing existing research gaps. The findings provide valuable insights for enhancing thermal performance, and controlling heat transfer locally, and have implications for medical treatments, thermal management systems and related fields. The research opens up new possibilities for precise thermal management and offers directions for future investigations.

Comparison of Size Distribution of Fish Obtained from Gill Netting and the Distributions of Echoes from Hydroacoustics in Lake Dejguny (Poland)

A procedure is proposed to assess the impact of various relationships found in the literature and is used to convert acoustic target strengths (TS) to fishes’ total length (TL) with respect to the compatibility of fish length data obtained from vertical hydroacoustics and gillnets. The study used one set of data collected with a 120 kHz echosounder across the mesotrophic, dimictic Lake Dejguny. Four general multi-species TS–TL relationships were tested for the maximum dorsoventral characteristic: (1) a relationship developed using mainly West Atlantic marine and brackish water fish for various frequencies, (2) a relationship developed using fish from the Salmonidae, Percidae, and Cyprinidae families at 120 kHz, as well as the relationship shown by two generalized equations for representatives of (3) the Cyprinidae family (200 kHz) and (4) the Percidae family (200 kHz). In addition, two other equations were developed for (5) perch (Perca fluviatilis) and (6) roach (Rutilus rutilus). The procedure for selecting the most appropriate TS–TL ratio began by determining the TS threshold that would eliminate small fish that were ineffectively caught with gillnets. Depending on the TS–TL relation, the threshold ranged from −48.5 dB to −45.5 dB, and the corresponding TL was in the range of 62.3–93.0 mm. Then, using linear regression, the relationship between the percentage of caught fish organized in length classes (TL), whose boundaries were determined using the tested TS–TL relationships, and the share of fish recorded acoustically in the corresponding TS classes (with a 1.5 dB interval) was examined. The fit of the regression model to the data (percentage) was assessed using the coefficient of determination r2, the mean absolute error (MAE), the Nash–Sutcliffe model efficiency coefficient (NSE), and root mean square error (RMSE). For the data from Lake Dejguny, the most similar distribution of fish echo proportions and the corresponding distribution of total length (TL) for fish larger than 62 mm were obtained using the TS–TL relation developed using fish from the Salmonidae, Percidae, and Cyprinidae families (2), and for fish larger than 74 mm, the relation was developed for the family Pericidae (4). No evidence was found to unambiguously verify the meanings of different sound frequencies (120 and 200 kHz) for which the TS–TL relationships used in the analysis were derived. The proposed procedure can be used to select the optimal regression equation.

Screening of Actinomycetes effects against Pathogen causing Bacterial Blight of Pomegranate

Pomegranate is called ‘fruit of paradise’ due to its versatile uses. Its fruit, leaves, stem all have nutritional as well as medicinal uses. However, pomegranate yield is adversely affected by infection of plant by various plant pathogens. One of the major harmful diseases is bacterial blight of pomegranate [commonly known as ‘telya disease’] caused by Xanthomonas axonopodis PV punicae. The pathogen affects the fruit, leaves as well as stem. A variety of approaches have been tried to control the disease including cultivation methods, use of botanicals, use of antibiotics, use of chemicals etc. However, no single therapy has been found to be a sure shot control method. The current research work has been designed to achieve the control of disease using biological agent. Here, specifically actinomycetes were isolated from healthy pomegranate cultivated soils. During this research, 24 different actinomycete cultures were isolated and purified. All these cultures were tested for antagonistic activity against bacterial blight pathogen by giant colony technique. The antagonistic activity was determined by calculating inhibition ratio. The inhibition ratio is the ratio of total length of inhibitory area to the total length of streak line. Some actinomycete isolates showed promising antagonistic activity against Xanthomonas axonopodis. Further work is in progress.

Feeding Rate and Protein Quality Differentially Affect Growth and Feeding Efficiency Response Variables of Zebrafish (Danio rerio).

Manipulating feeding rate and protein quality may improve growth and feeding efficiency of cultured species. However, whether feeding rate, protein quality, or their interaction has a greater effect on growth and feeding efficiency response variables is unknown. To determine whether feeding rate and protein quality individually or interactively affect growth and feeding efficiency, juvenile Zebrafish (Danio rerio) were either offered nutritionally similar diet consisting of either menhaden fishmeal protein or a 100% replacement of fishmeal with soybean meal-based protein restrictively or to satiation. Total length, weight, feed intake, and feed conversion ratio (FCR) were measured throughout the duration of the study. Protein quality and feeding rate individually and interactively affected feed intake and FCR: Zebrafish offered feed to satiation had higher growth and FCR than those fed restrictively, and Zebrafish fed soybean meal-based diet showed lower growth and higher FCR and feed intake compared to those fed fishmeal-based diet, although magnitude of response depended on feeding rate. These findings likely indicate lower digestibility of soybean meal or the presence of antinutritional factors in soybean meal that led to impaired nutrient absorption of fish offered soybean meal-based diet. Differences in measured response variables between protein qualities and feeding rates highlight the importance of determining interactive effects in nutritional studies.

Morphometric Relationships, Growth and Condition Factors of Critically Endangered Chinese Pangolin (Manis pentadactyla).

Simple SummaryThe pangolin is the only scaly mammal in the world. Among the eight extant pangolin species, the Chinese pangolin (CP) is most threatened with extinction. Thus, this species is categorized as “Critically Endangered” by the International Union for Conservation of Nature (IUCN) and listed under “Appendix I” of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Taiwan is a single Formosa Island where the population of CP has been increasing for the last decade due to continuous conservation initiatives. The presence of sufficient samples of CP that are adapted to distinct environmental conditions could provide valid morphometric results. However, the morphometric relationships, growth type, and condition factors have not yet been enumerated for any pangolin species including Chinese pangolin. The study included 282 rescued and rehabilitated individuals from central and southern Taiwan. Adult male and female pangolins measure between 75.2–103 cm and 66–114.9 cm from the snout to the tip of the tail and weigh between 4–7.6 kg and 3–5.8 kg, respectively. Adults also showed negative allometric growth (b < 3) as their length increased. However, the average relative condition factor (KR) was 1.02 ± 0.16 and showed the majority of rescued adults in normal (59.7%) and good (39%) health conditions.Morphometric relationships and condition factors are crucial to quickly understanding the fitness and well-being of animals. Total length (cm) and bodyweight (g) of 282 (male = 167 and female = 115) pangolins were accounted for in this study which was received and rehabilitated in Pingtung Rescued Center, Pingtung and Endemic Species Research Institute, Nantou, Taiwan. The allometric equation; W = aLb was used to estimate the length-weight relationships where R2 = 0.70, a = 0.61, and b = 1.98. The ratio of total body length and tail length was between 1.1 and 2.7. Pangolins exhibited negative allometric growth (b < 3) as their length increased. The average relative condition factor (KR) was 1.04, indicating a state of good health for rescued individuals. However, Fulton condition factor (KF) and KR fluctuated in different months but was significantly heavier during the wet seasons. This study recommended to release healthy animals with KF of 0.8 or higher back into the wild in order to increase their survival rate. The study, thus will be helpful to promote standardized guidelines for conducting physical measurements and understanding health status. Additionally, it will support the recovery of this threatened species by husbandry and diet management in ex-situ and in-situ conservation.

Multi-objective constructal design for compound heat dissipation channels in a three-dimensional trapezoidal heat generation body

A three-dimensional compound heat dissipation channel model with both heat conduction and fluid channels in a trapezoidal heat generation body is established in this paper. Firstly, constructal design of the model is conducted by taking the composite function of maximum temperature difference and pumping power consumption as the optimization objective based on the weighted sum method. The optimization results with compound heat dissipation channel and pure fluid channel are compared. Secondly, the Pareto optimal set also obtained by the multi-objective optimization to satisfy different design requirements based on the NSGA-II algorithm. The results show that there exist the optimal fluid channel radius, ratio of trapezoidal height to total length and length ratio of elemental channels to make the composite function of the trapezoidal heat generation body approach its minimum. Compared with the initial design, the composite function is reduced by 25.7% after constructal optimization with three design variables. The result obtained by the weighted sum method is also located at the Pareto optimal set, which simultaneously verifies the results obtained by the weighted sum method and multi-objective optimization method. The optimization results may provide a new theoretical guideline for the designs of various electronic devices.

Design optimization of trio concept combustor geometry for low-grade biomass producer gas combustion

Biomass as carbon-neutral fuel is a promising alternative to mitigate global warming problems. Biomass conversion into producer gas (PG) through air gasification allows the co-firing of PG burners with fossil fuel burners in boilers for large scale power generation. However, PG is highly diluted with nitrogen which reduces the heating value resulting in significantly higher PG flow, eliminating the possibility of using conventional compact gas burner designs. To burn the low-grade PG, special design for the combustor is required. Novel combustor design which combined three theories of swirl vane, cyclonic and staged combustion to facilitate PG combustion in compact geometry was elaborately investigated. Flow hydrodynamics and combustion characteristics of low-grade PG were studied using ANSYS-FLUENT simulation software. Design of Experiments (DOE) method was applied to optimize the design of the combustor geometry. The arrangement of simulations was designed based on the instruction of DOE. The optimum geometry design of combustor was 500 mm combustor length, 150 mm combustor diameter, 60° swirl vane angle and 0.4 secondary inlets position to total combustor length ratio. The combustor achieved optimum performance of 1965 K outlet temperature, 18 ppm CO emissions and 33 ppm NOx emissions at slight lean condition with equivalence ratio of 0.9.

Morphometric Analysis of Khag Micro-Watershed in North-West Himalayas of Kashmir Using GIS and Remote Sensing Techniques

Morphometric analysis is of vital importance in any hydrological research and is inevitable in development and management of watershed. Using the watershed as the main unit of morphometric characterization is the most logical choice, as well as geomorphological and hydrological processes take place within the drainage basin. A critical assessment and evaluation of morphometric parameters of Khag micro-watershed was accomplished through measurement of relief, linear and aerial aspects using Geographical Information System (GIS). The watershed boundaries, aspect, slope, digital elevation model (DEM), profile graph of topography, drainage order and drainage density mapswere generated for detailed study of micro-watershed using Shuttle Radar Topographic Mission (SRTM) data. The study area was designated as fourth order basin with the drainage area of 34.32 km2 and shows dendritic drainage pattern. The total length, drainage density and mean bifurcation ratio (Rb) were found to be 38.84 km, 1.13km/km2 and 1.73, respectively. The Khag micro-watershed showed the greater Rb value, which directs a strong structural control in the runoff pattern. A decrease in the stream frequency of flow was also observed with an increase in the order of flow. The shape parameters such as circulatory ratio, elongation ratio, length of over land flow, form factor and drainage texture of Khag micro-watershed were 0.42, 0.56, 0.43 km, 0.24 and 1.66, respectively. The Khag micro-watershed is elongated in shape and dendritic in drainage pattern. This can be attributed to the fact that the lithology and structural controls are more or less uniform. Relative relief and ruggedness number were 0.065 and 2.39 and are likely to subject the micro watershed to maximum soil erosion that demands, instantaneous soil conservation measure to be taken by watershed managers for its stability and sustainability. These studies area advantageous for the planning of rainwater harvesting and the management of the catchment area.

First record of Lobothorax typus from Odisha coast, India, with molecular characterization and observation of its biphasic moulting.

Two distinct morphologies of Cymothoidae isopod, Lobothorax typus were collected from the marine water of Bay of Bengal, Goapalpur-on-Sea as the first record of this parasite from coastal water of Odisha, India. All specimens were found attached to the buccal region of different individuals of the same host fish Trichiurus lepturus. With the aid of COI gene sequencing and morphological analysis, the individuals were found to be conspecific. The most prominent variation among the two morphologies includes the size of 5th pereonite and pleon length to total body length ratio. These variations are as a result of the biphasic moulting process. Maximum Likelihood tree analysis based on COI gene sequences concluded the monophyletic taxonomy of different buccal attaching genera under the family Cymothoidae which is in congruence with their morphological divergence.

Identification and characterization of novel QTL conferring internal detoxification of aluminium in soybean.

Aluminium (Al) toxicity inhibits soybean root growth, leading to insufficient water and nutrient uptake. Two soybean lines ('Magellan' and PI 567731) were identified differing in Al tolerance, as determined by primary root length ratio, total root length ratio, and root tip number ratio under Al stress. Serious root necrosis was observed in PI 567731, but not in Magellan under Al stress. An F8 recombinant inbred line population derived from a cross between Magellan and PI 567731 was used to map the quantitative trait loci (QTL) for Al tolerance. Three QTL on chromosomes 3, 13, and 20, with tolerant alleles from Magellan, were identified. qAl_Gm13 and qAl_Gm20 explained large phenotypic variations (13-27%) and helped maintain root elongation and initiation under Al stress. In addition, qAl_Gm13 and qAl_Gm20 were confirmed in near-isogenic backgrounds and were identified to epistatically regulate Al tolerance via internal detoxification instead of Al3+ exclusion. Phylogenetic and pedigree analysis identified the tolerant alleles of both loci derived from the US ancestral line, A.K.[FC30761], originally from China. Our results provide novel genetic resources for breeding Al-tolerant soybean and suggest that internal detoxification contributes to soybean tolerance to excessive soil Al.

A Method to Identify the Sex of Cultured Eel (Anguilla japonica) using the Pectoral Fin Length: Total Body Length Ratio

Previous methods for identifying the sex of eels were difficult to apply to yellow eels due to their undeveloped gonads. In this study, we investigated easy method to identify the sex of cultured eel, Anguilla japonica, using the ratio between the vertical and horizontal length of the pectoral fin and total body length. Females had longer total body length (TL):horizontal fin length (Fh) and TL:vertical fin length (Fv) ratios than males. Based on our results, we found that both the TL:Fh and the TL:Fv ratio were suitable for determining the sex of cultured yellow eel. We therefore suggest using the TL:Fh ratio to determine the sex of yellow eels under natural conditions (i.e. without anesthetizing or sacrificing the eels). Specially, eels with TL:Fh ratios below and above 31.6 should be identified as males and females. To our knowledge, this is the method to determine the sex of yellow eel.

Design of infrared dual-band common path annular aperture ultrathin imaging system

In order to solve the problems of the large number of components and complex structure in the mid-long wave infrared dual-band system, the structural characteristics of the annular folded imaging system was analyzed, and the calculation method of the obscuration ratio was explained. An infrared dual-band annular aperture ultrathin imaging system with common path was designed. The focal length is 50 mm, the field of view is 14°, and F number is 1. The system is made up of only one optical element, so it has simple structure and compact optical path. The ratio of total optical length to focal length is 0.48. At the spatial frequency of 20 lp/mm, the modulation transfer function (MTF) of the full field of view is more than 0.45 in medium wave infrared 3-5 μm, and that is more than 0.30 in long wave infrared 8-10 μm. The athermalization of system is realized in the range of −40-80 ℃. According to the tolerance results, this system is machinable. The chalcogenide glasses used for the substrate material can be precision molded to achieve batch processing. The study provides a new idea for the realization of low-cost and miniaturized infrared dual-band system.

Hydrodynamic Analysis in Redesigning a Monohull Passenger Ship into a Catamaran

In line with technological developments, many studies have led to the factors that consider hull shape planning. Therefore, innovations in hull form planning are the primary basis for obtaining a hull that is considered efficient in reducing ship resistance and fuel consumption. This study aims to modify the design of a monohull and transform it into a catamaran while maintaining the total length and Displacement ratio. The ship model used is the Monohull passenger ship with a rounded shape and modified to become a catamaran with a chine shape. The hull chine symmetrical was determined by stagger to the length ratio of S/L 0.3. The hydrodynamic investigations and calculations of models using Computational Fluid Dynamic (CFD). Analysis hydrodynamic on both hulls carried out on the components of total resistance, viscous resistance, friction resistance, and wave resistance with variations of Froude number: 0.3: 0.5: 0.7: 0.9 and 1.2. From the results of the analysis, it is found that the calculation of the coefficient of resistance on the catamaran with the Chine hull is smaller than the monohull. Fn 0.7 at S/L 0.3, the catamaran produces a resistance coefficient that is more favorable than the other speeds.

Numerical modeling on varying patch repair size of cracked beam using engineered cementitious composites

PurposeThis study aims to investigate the size effect of the patched repairing material applied to the cracked beam.Design/methodology/approachNumerical analysis was conducted on a simply supported cracked beam with a dimension of 200 × 25 × 15 cm using ABAQUS software. The behavior of concrete and engineered cementitious composites (ECC) in the simulation are described as concrete damage plasticity model. Linear elastic-plastic model was used to represent the behavior of rebar steel. The type of patching consisted of the varying ratio of lengths and depths, including patching length to total length ratios of 0.2, 0.3 and 0.4, and patching depth to total depth ratios of 0.2, 0.3, 0.4 and 0.5.FindingsResults show that variations in the patching length and depth ratios affect the maximum flexural load, stiffness and ductility of the repaired beam. It was also found that repairing the cracked beam by using ECC provides higher flexural load of the beam than the use of conventional concrete, owing to the superior tensile strength of ECC.Originality/valueECC is the cementitious-based mortar that contains the special selected poly vinyl alcohol fiber having high tensile strength. ECC has been known to exhibit high ductility, high tensile strength and improve durability performance. Thus, ECC is suitable as repairing material for patching cracked beam. By investigating the size of the patched repairing material applied to the cracked beam, the structural performance of repairing beam and the effectiveness of the various patching size were achieved.

Design of achromatic annular folded lens with multilayer diffractive optics for the visible and near-IR wavebands.

In this paper, the annular folded lens (AFL) is applied to the realization of a miniaturized system for the visible and near-IR spectrums (0.45-1.1μm). In order to correct the chromatic aberration, a hybrid AFL is designed with the multilayer diffractive optical element (MLDOE) in which the substrate materials are precision molded glasses. We propose a new design method of the MLDOE to improve the polychromatic integral diffraction efficiency (PIDE) that makes it suitable for the optical path of the AFL. By comparing the characteristic angle weighted PIDE (CAW-PIDE), the optimal microstructure heights of the MLDOE can be obtained, and the effect of diffraction efficiency on image quality can be minimized for the entire incident angle range. The design results show that the ratio of total length to the focal length is only 0.332, and comprehensive modulation transfer function considering the diffraction efficiency is larger than 0.26 at 166 lp/mm. This study can provide a new idea for designing a broadband, miniaturized, and low-cost imaging system.

Risk Factors for Major Hemorrhage Following Percutaneous Image-Guided Renal Biopsy: What is the "core" of the Problem? A Retrospective Case-control Study.

Objectives:Percutaneous renal biopsy (PRB) plays a critical role in the work-up of renal parenchymal disease. Although it is considered a low-risk procedure, additional interventions may be required in about 7% of the cases following biopsy. The purpose of this study was to identify risk factors for major hemorrhage by microscopic analysis of the cores obtained following PRB, with an intent to enhance the sensitivity and specificity of the risk stratification process, especially in patients undergoing this procedure in an outpatient setting.Material and Methods:A retrospective review identified 17 of 179 patients (9.50%) with major hemorrhage following PRB between July 2014 and June 2019. Using propensity score matching, 26 controls (without major hemorrhage) were matched to 17 cases (with major hemorrhage). The biopsy cores obtained from the cases and controls were analyzed by a single pathologist for medullary, cortical, total (medullary + cortical) lengths, and the number of arcuate arteries (AAs). Medullary:cortical (M:C), cortical:total (C:T), and medullary:total (M:T) length ratios were then calculated.Results:A stratified version of logistic regression was used to test for an association between each of the variables identified on the cores and the probability of a major hemorrhage. The analysis revealed that there was a statistically significant association between the number of AAs per specimen with the risk of major hemorrhage (P = 0.0006). When 0, 1, or >2 AAs were identified, the frequency of major hemorrhage was 13.04%, 66.67%, and 75.00%, respectively. The odds of major hemorrhage were 6 times higher with one AA and (95% CI, 1.28–32.30) and 15 times higher with >2 AAs (95% CI, 1.41–169.57). No significant association was found between medullary length (P = 0.228), medulla:cortex (M:C) (P = 0.089), medulla:total (M:T) (P = 0.108), or cortex:total (C:T) (P = 0.112) length ratios and major hemorrhage.Conclusion:There was a strong and incremental correlation between major renal hemorrhage following PRB and the number of AAs per core specimen. Identification of AAs by the pathologist, while assessing for sample adequacy, in the US suite can help predict major hemorrhage in patients undergoing PRBs.

Insight into the fracturing of silty mudstone in cyclic hydrothermal environments based on computed tomography

The objective of this study was to examine the fracture evolution and related mechanism of silty mudstone in cyclic hydrothermal environments. Fracture evolution tests and computed tomography (CT) scans were carried out on silty mudstone specimens subjected to cyclic wetting-heating. The spatial–temporal variations of fracture parameters including the total length ratio, fracture rate, mean fracture width, fracture direction and fractal dimension were investigated. The mechanism underlying the fracture evolution in silty mudstone was also analyzed. The results show that fractures initiate and propagate from the wetting-heating surface down to the deep layer with increasing cycle number. Most of the fractures are parallel or perpendicular to each other and form a reticulate fracture network on every horizontal cross-section. The total length ratio, fracture rate, mean fracture width and fractal dimension considerably decrease as the depth increases, and the total length ratio and fracture rate significantly increase with increasing cycle number. After a wetting-heating cycle, only the zone within a depth of 14 mm shows slight fracturing; however, after 17 wetting-heating cycles, slight fracturing occurs within a depth of 104 mm. The fracture mechanism mainly involves the hydrothermal stress effect, water-softening effect, and mineral hydrolysis.

Morphology and Molecular Biology of Benthic Java Sea Shark Ray Rhina ancylostoma Bloch and Scheider 1801 (Elasmobranchia: Rhinidae)

Aims: Morphology and molecular biology of a rare shark-rays Rhina ancylostoma caught from Java sea.Indonesia.&#x0D; Study Design: Morphology, morphometry and DNA analysis of the fish specimen.&#x0D; Place and Duration of Study: Sample wascollected from fish auction hall at north Java, specimen now stored in Lab of Ichtiology. Department of Fisheries. Faculty of Fisheries and Marine Science. Diponegoro University, between March to December 2019.&#x0D; Methodology: DNA extraction, amplification and molecular identification of fish sample.Yield of DNA supernatant transferred in an eppendeorf tube and stored in 4°C for further process. PCR amplification. Part of Mithocondrial DNA COI (Cytochrome Oxidase subunit-I) gen was amplified using Polymerase Chain Reaction (PCR) method. Then matched up with GenBank database at NCBI using Basic Local Alignment Search Tool (BLAST) analysis. Philogenetic tree was set using Neighbor-Joining method, Kimura-2 parameter model and 1,000 bootstrap replication. Some sequence from NCBI GenBank were inputted into philogenetic tree as comparison.&#x0D; Results: Rhina ancylostoma as one of demersal shark rays catch from tropical shallow Java sea. Range of Total Length 73 – 200 cm and dominant Total Length catch 125 cm. Morphologyis characterised with three lines of spine thorn on the head, morphometry characteriswide of head to TL ratio 0.77. DNA analysis had confirmed the specimen of AH2 as Rhina ancylostoma based on homological match up of sequence of Gen Bank database with reference accesion number KU721837.1 with length sequence of 665 bpand identical similarity of 99.84% for specimen Accession number LC 505461.&#x0D; Conclusion: Rhina ancylostoma as one of demersal shark rays catch from Java sea. Range Total Length (TL) of catch 73 – 200 cm and dominant TL catch range 101 – 125 cm. Morphologically character of wide head ratio with three lines of spine thorn on the head. Nearest genetic distance of 0.02 to Rhincobatushorkelii and 0.017 to R. australiae. Longest genetic distance of 0.243 to Potamotrygon motoro.