The investigation of the scale effect on porosity in Bashkirian limestones

The article presents the methodology of the representative elementary volume definition for two 1 m long whole core segments. Scientific articles focused on practical methods of representative volume calculations using various physical parameter fluctuations have been studied. Porosity values of every whole core fragment evaluated in two ways using the 7.3 cm diameter core samples in the first approach and the 3 cm diameter core samples in the second one have been compared. Particularities of the scale effect occurring in core samples and depending on core size and porosity type have been analyzed. The cause of porosity increase in big core samples has been determined. The reason due to which porosity changes are explained by fracture porosity occurring in core samples having big volumes has been found. The comparison between neutron log porosity and core porosity has been made. Reasons of similarities or differences of core and log data have been established.

Tutorial: A Century of Sidewall Coring Evolution and Challenges, From Shallow Land to Deep Water

Due to the high cost of conventional coring operations, rotary sidewall coring has become increasingly important, particularly for deepwater operations. The rig costs, operational challenges, and amount of time involved to core wells below 30,000 ft are considerable, even for wireline operations. As wells get deeper, formation pressures will exceed 30,000 psi, and differential pressures can exceed 10,000 psi, which will eclipse the capabilities of traditional rotary coring tools. New technology has been introduced to enhance the recovery of rotary sidewall cores to improve operations and capabilities on these challenging wells that will be the primary subject of this paper. This new technology can also enhance coring operations and reliability for land and other offshore operations, in addition to deep water. New improvements and challenges include: * Reliable 1.5-in.-diameter core samples, with a 35,000-psi-rated tool * New high-powered coring tools with enhanced energy to address cutting Lower Tertiary wellcemented formations (Wilcox, Lower Miocene, etc.) * Higher torque and horsepower at the bit to enhance cutting and prevent stalling when coring * High-powered surface systems along with highstrength and high-power wireline cables * Upgrades to address high temperatures, highdifferential pressures, high-mud viscosity, large (24 in.) boreholes, and improved reliability * New drill bits and catcher rings to use a high-power system and operate in harsh coring environments * New cutting, retrieval, and core handling advancements for reliability in hard, consolidated formations * Combinability upgrades to reduce wireline trips and reduce rig costs for coring * Dual-coring tools with the ability to have different catcher rings and bits downhole simultaneously on a single run, along with tool redundancy downhole for improved reliability * Combination of rotary coring and formation sampling operations to obtain formation pressures, fluid samples, and rotary sidewall cores on a single run * Downhole monitoring of the coring operation, which includes drilling functions like torque, bit force, penetration rate, core bit penetration, and recovered core length, along with tool orientation * Core recovery information to enable 100% core verification downhole, so extra cores are not cut unnecessarily during the job, with individual core plugs measured and verified downhole * A unique method to seal the cores in a pressurecompensated coring tube downhole to capture all the formation fluids in the rock in downhole conditions * Complete rotary coring downhole operations can be monitored remotely for offsite interaction during the coring operation Besides reviewing historical coring tools and techniques, new technology is also discussed in more detail. The new technology starts with the introduction of the 1.5-in.-diameter rotary sidewall coring tools for deep water over a decade ago. Many applications and technologies are presented to show their effectiveness for deepwater operations. The successful examples include acquiring 1.5-in. cores in large boreholes, hard formations, deep wells, high-differential pressures, and extreme hydrostatic pressure. There are also examples of new technology available for future operations, including dual coring, combination coring, and sealed pressurized coring.

Adaptation of the Winkie Drill for subglacial bedrock sampling

The Winkie Drill is an agile, commercially available rock coring system. The U.S. Ice Drilling Program has modified a Winkie Drill for subglacial rock and ice/rock interface coring, as well as drilling and coring access holes through ice. The original gasoline engine was replaced with an electric motor though the two-speed gear reducer and Unipress hand feed system were maintained. Using standard aluminum AW34 drill rod (for 33.5 mm diameter core), the system has a depth capability of 120 m. The drill uses forward fluid circulation in a closed loop system. The drilling fluid is Isopar K, selected for favorable properties in polar environment. When firn or snow is present at the drill site, casing with an inflatable packer can be deployed to contain the drill fluid. The Winkie Drill will operate from sea level to high altitudes and operation results in minimal environmental impact. The drill can be easily and quickly assembled and disassembled in the field by two people. All components can be transported by Twin Otter or helicopter to the field site.

Acetic acid concentration estimation using plastic optical fiber sensor based surface Plasmon resonance

Optical fiber chemical sensor based surface Plasmon resonance for sensing and measuring the refractive index and concentration for Acetic acid is designed and implemented during this work. Optical grade plastic optical fibers with a diameter of 1000μm were used with a diameter core of 980μm and a cladding of 20μm, where the sensor is fabricated by a small part (10mm) of optical fiber in the middle is embedded in a resin block and then the polishing process is done, after that it is deposited with about (40nm) thickness of gold metal and the Acetic acid is placed on the sensing probe.

Two sub-millimetre bright protoclusters bounding the epoch of peak star-formation activity

ABSTRACT We present James Clerk Maxwell Telescope Submillimetre Common-User Bolometer Array 2 (SCUBA-2) 850 and 450 $\mu$m observations (σ850 ∼ 0.5 mJy, σ450 ∼ 5 mJy) of the HS1549+19 and HS1700+64 survey fields containing two of the largest known galaxy overdensities at z = 2.85 and 2.30, respectively. We detect 56 sub-millimetre galaxies (SMGs) with SNR > 4 over ∼50 arcmin2 at 850 $\mu$m with flux densities of 3–17 mJy. The number counts indicate overdensities in the 3-arcmin diameter core region (∼1.5 Mpc at z = 2.5) of $6^{+4}_{-2}\times$ (HS1549) and $4^{+6}_{-2}\times$ (HS1700) compared to blank field surveys. Within these core regions, we spectroscopically confirm that approximately one-third of the SMGs lie at the protocluster redshifts for both HS1549 and HS1700. We use statistical identifications of other SMGs in the wider fields to constrain an additional four candidate protocluster members in each system. We combine multiwavelength estimates of the star-formation rates (SFRs) from Lyman-break dropout- and narrow-band-selected galaxies, and the SCUBA-2 SMGs, to estimate total SFRs of 12 500 ± 2800 M⊙ yr−1 (4900 ± 1200 M⊙ yr−1) in HS1549 (HS1700), and SFR densities (SFRDs) within the central 1.5-Mpc diameter of each protocluster to be 3000 ± 900 M⊙ yr−1 Mpc−3 (1300 ± 400 M⊙ yr−1 Mpc−3) in the HS1549 (HS1700) protocluster, ∼104 × larger than the global SFRDs found at their respective epochs, due to the concentration of star-forming galaxies in the small volume of the dense cluster cores. Our results suggest centrally concentrated starbursts within protoclusters may be a relatively common scenario for the build-up of mass in rich clusters assembling at z ≳ 2.

Genetic parameters for hair characteristics and core body temperature in a multibreed Brahman–Angus herd1

Thermal stress in hot humid conditions limits cattle production. The objectives for this study were to estimate genetic parameters for hair characteristics and core body temperature under low and high temperature humidity index (THI) conditions. Hair samples were collected and measured for length and diameter. Core body temperature was measured as vaginal temperature every 15 min over a 5-d period using an iButton temperature measuring device implanted in a blank CIDR in 336 heifers from the University of Florida multibreed herd (ranging from 100% Angus to 100% Brahman). Restricted maximum likelihood procedures were used to estimate heritabilities from multiple bivariate animal models using the WOMBAT program. Estimates of heritability for hair diameter, undercoat length, topcoat length, body temperature under low THI conditions, and body temperature under high THI conditions were 0.50, 0.67, 0.42, 0.32, and 0.26, respectively. The genetic parameters estimated in this study indicate a large, exploitable genetic variance which can be selected upon to improve tolerance in cattle. Breed effects for differing compositions of Brahman and Angus were also estimated. As Brahman breed composition increased by 25% undercoat length, topcoat length, body temperature under low THI conditions, and body temperature under high THI conditions decreased by 1.32 mm, 2.94 mm, 0.11 °C, and 0.14 °C, respectively. Under both low and high THI conditions, cattle with 25% Brahman breed composition or greater maintained a significantly lower body temperature than the 100% Angus breed group. The incorporation of Brahman germplasm is recommended for herds that often experience heat stress conditions in order to increase resilience to heat stress.

Understanding volcanic facies in the subsurface: a combined core, wireline logging and image log data set from the PTA2 and KMA1 boreholes, Big Island, Hawai`i

To help understand volcanic facies in the subsurface, data sets that enable detailed comparisons between down-hole geophysical data and cored volcanic intervals are critical. However, in many cases, the collection of extended core intervals within volcanic sequences is rare and often incomplete due to challenging coring conditions. In this contribution we outline and provide initial results from borehole logging operations within two fully cored lava-dominated borehole sequences, PTA2 and KMA1, on the Big Island of Hawai`i. Data for spectral gamma, magnetic susceptibility, dipmeter resistivity, sonic, total magnetic field, temperature and televiewer wireline logs were successfully acquired for the open hole interval ca. 889 m to 1567 m within the PTA2 borehole. Spectral gamma was also collected from inside the casing of both wells, extending the coverage for PTA2 to the surface and covering the interval from ca. 300 to 1200 m for KMA1. High-quality core material was available for both boreholes with almost complete recovery which enabled high-resolution core-to-log integration. Gamma data are generally low commonly in the range ca. 7–20 gAPI but are shown to increase up to API of ca. 60 with some intrusions and with increases in hawaiite compositions in the upper part of PTA2. Velocity data are more variable due to alteration within porous volcanic facies than with burial depth, with a general degrease down-hole. The high-resolution televiewer data have been compared directly to the core, enabling a comprehensive analysis of the variations in the televiewer responses. This has enabled the identification of key features including individual vesicles, vesicle segregations, strained vesicles, chilled margins, rubble zones, intrusive contacts and pāhoehoe lobe morphologies, which can be confidently matched between the televiewer data and the full diameter core. The data set and results of this study include findings which should enable improved borehole facies analysis through volcanic sequences in the future, especially where down-borehole data and images but no core are available.

Evaluasi Mutu Beton Menggunakan Beton Inti Diameter Kecil

Salah satu penyebab keterbatasan pengambilan sampel beton inti karena keberadaan tulangan pada struktur beton. Jika digunakan diameter core besar, dapat menurunkan kapasitas struktur beton dengan adanya tulangan yang terpotong. Oleh karena itu, dilakukan studi penggunaan core beton diameter kecil untuk memprediksi kuat tekan beton diameter kecil terhadap silinder beton diameter standar. Benda uji berupa (a) silinder beton berdiameter 10 cm dan tinggi 20 cm; (b) 2 plat beton berdimensi 45cm x 45cm x 13cm; dan (c) 4 balok beton berdimensi 70cm x 30cm x 15cm. Metode pengambilan sampel core diameter 2 inchi dan 1 inchi dengan arah sejajar dan tegak lurus arah pengecoran. Ada 2 variasi mutu beton yaitu 20 MPa dan 30 Mpa dengan MSA masing-masing 10 mm dan 20 mm. Pengujian kuat tekan dan modulus elastisitas beton dilakukan, serta uji normalitas beton inti untuk mengevaluasi kecukupan benda uji. Dari hasil pengujian dapat disimpulkan bahwa kuat tekan beton inti 2 inchi dengan pengambilan benda uji sejajar dan tegak lurus arah pengecoran memenuhi syarat uji normalitas, sehingga dapat direkomendasikan dengan jumlah sampel 25 buah, sedangkan untuk sampel berdiameter 1 inchi jumlah sampelnya perlu ditambah

Silica Nanoparticle Synthesis and Multi-Method Characterisation

The information provided by different characterisation methods when measuring particle size varies depending on the chosen technique and analytical approach (e.g. light scattering, transmission electron microscopy, spectroscopy, x-ray scattering). This in turn has an impact on the accuracy of the results as well as comparability between methods and overall confidence on the analyses. The present study used a common sol-gel reaction to synthesise amorphous silica nanoparticles (aSiNPs) and characterised the product purity and homogeneity. The reaction involved hydrolysis and condensation of tetraethyl orthosilicate (TEOS) in the presence of lysine, which acted as catalyst for the silica production and also as a capping agent for particle size control in a suspension kept at pH 8-10. According to DLS data, the stock suspension was stable for at least 6 months in Milli Q water without surfactant when kept at 4°C. This study focused on multi-method size and shape characterisation of the aSiNPs, involving the following techniques: DLS, TEM, FTIR, STEM and SAXS. These techniques provided information on hydrodynamic diameter, core particle dimensions, sphere equivalent size, and radius of gyration. Our results show two particle populations, one around 2 nm and the other around 7 nm in diameter. Notably, these two populations are not resolved (i.e. “visible”) by all methods used.