bluuebunny/crossref_metadata_2025 huggingface dataset:
Ứng dụng thuật toán LIGHTGBM trong phân loại lớp phủ huyện Đảo Lý Sơn, Việt Nam.
Authors: Vương Tấn Công , Phạm Hoàng Hải
Published: August 2023

Hệ thống đảo của Việt Nam có phần quan trọng trong việc xây dựng những tiền đồn vững chắc để bảo vệ an ninh chính trị, độc lập chủ quyền của quốc gia trên biển và là thế bàn đạp phát triển kinh tế biển. Tại khu vực miền trung, huyện Đảo Lý Sơn có vai trò quan trọng trong phát triển kinh tế xã hội và đảm bảo an ninh quốc phòng. Nghiên cứu này đề ứng dụng mô hình phân loại LightGBM sử dụng tư liệu ảnh vệ tinh SPOT trong phân loại lớp phủ sử dụng đất. Kết quả cho thấy mặc dù với số lượng mẫu nhỏ, độ chính xác của mô hình (OA = 0,9). Mô hình huấn luyện được sử dụng cho phân loại lớp phủ sử dụng đất tại khu vực nghiên cứu, làm cơ sở cho đánh giá tổng hợp tài nguyên thiên nhiên tại huyện đảo Lý Sơn.
Sigara Kullanımının Palatal Çiğneme Mukozasının Mikrosirkülasyonu ve Kalınlığı Üzerine Etkisinin Değerlendirilmesi
Authors: GÜRBÜZ Sühan , TURGUT ÇANKAYA Zeynep , KURTİŞ Mazlum Bülent
Published: August 2023

Amaç: Bu çalışmada sigara kullanımının yumuşak doku ogmentasyonunda alıcı saha olarak kullanılan palatal çiğneme mukozasındaki mikrosirkülasyona ve kalınlığa etkisinin değerlendirilmesi ve mukoza kalınlığı ile mikrosirkülasyon arasındaki ilişkinin belirlenmesi amaçlanmıştır.

Gereç ve Yöntem: Çalışmamıza yaşları 28-48 arasında değişen sigara kullanan (n=16) ve kullanmayan (n=15) diş eti çekilmesi nedeniyle kliniğe başvurmuş olan hastalar dahil edildi. Bu hastalardaki palatal mukoza kalınlığı anterior ve posterior bölgede transgingival sondlama yöntemi ile kaydedildi. Mukozanın mikrokanlanması ise laser Doppler flowmetri (LDF) aracılığı ile siyanoakrilat ile sabitlenerek perfuzyon ünitesi (PU) cinsinden veriler kaydedildi. Verilerin istatistiksel analizleri bağımsız iki örnek t-testi veya Mann Whitney U testi ile yapıldı.

Bulgular: Palatal mukoza kalınlığı ve LDF ölçümlerinin ortalaması sırasıyla anterior bölgede 3.5 mm ve 183 PU iken, posterior bölgede ise 2.7 mm ve 218 PU bulundu. Sigara kullanan hastalarda, kullanmayanlara göre perfüzyon ünit ve palatal mukoza kalınlıkları yönünden aralarında istatistiksel farklılık görülmedi. Palatal mukoza kalınlığının anteriorda posteriora göre istatistiksel olarak daha yüksek olduğu, LDF’nin ise daha düşük olduğu bulgulandı (p
Stillbirths in relation to sow hematological parameters at farrowing: A cohort study
Authors: Bhattarai Sheeva , Framstad Tore , Nielsen Jens Peter
Published: August 2023

Objective: To determine associations between stillbirths and sow hematological parameters at farrowing. Materials and methods: A total of 160 sows from a high-performing Danish farrow-to-finish herd were chosen for the study. Standard hematological parameters were measured in sows within nine days before farrowing. At farrowing, dead piglets were collected and stillborns were identified using a lung floatation technique. The number of live-born piglets and parity of the sow was recorded after termination of farrowing. A generalized linear model was fitted to analyze the associations between each hematological parameter and the probability of stillbirth. Results: The mean (standard deviation) sow hemoglobin concentration before farrowing was 108.5 (8.6) g/L. In total, 29 sows (18.1%) were anemic ie, hemoglobin concentration below 100 g/L. The mean number of total born and stillborn piglets per litter was 16.3 (4.1) and 1.2 (2.2), respectively. The average parity of sows was 2.8 (1.8). Piglet stillbirth was associated with several hematological parameters of the sow, namely hemoglobin concentration, mean cell hemoglobin concentration, mean corpuscular hemoglobin, red blood cell distribution width, hemoglobin distribution width, platelet distribution width, number of reticulocytes, reticulocyte hemoglobin content, and reticulocyte cellular volume. Parity of the sow and total number of piglets born per litter were also associated with stillbirths. Implications: The probability of piglet stillbirth in this study is affected by several hematological parameters of the sow. There is also an association between probability of stillbirth and parity of the sow.
General overview of the detection of Mycoplasma hyopneumoniae DNA by quantitative polymerase chain reaction in diagnostic cases submitted to the Iowa State University Veterinary Diagnostic Laboratory from 2004 to 2016
Authors: Rawal Gaurav , Arruda Paulo , Rademacher Christopher , Bi Ran , Linhares Daniel
Published: August 2023

Mycoplasma hyopneumoniae (Mhp) is the etiologic agent of enzootic pneumonia and a major causative agent of the porcine respiratory disease complex. This study summarizes and describes the general diagnostic trends on Mhp detection by quantitative polymerase chain reaction (qPCR) in cases submitted to the Iowa State University Veterinary Diagnostic Laboratory from 2004 to 2016. The following variables were included in the analysis: animal age, geographic location, sample type, season, and submission year. The overall frequency of detection found was 27.04% and ranged from 17.9% to 40.7%. Lung homogenate and bronchial swabs had a greater Mhp qPCR detection rate than other sample types (P < .001) followed by bronchoalveolar lavage (P < .001), while oral fluids had the lowest Mhp detection rate (P < .001). The fall season had a greater percentage of positive Mhp qPCR results when compared to other seasons (P < .001), while spring had the lowest percentage. Finishing-age pigs had a greater percentage of Mhp qPCR detection when compared to other age groups (P < .001), while suckling pigs had the lowest percentage (P < .001).
Comparison of shower-in and shower-in plus bench entry protocols for prevention of environmental contamination due to personnel entry in a commercial swine facility
Authors: Anderson Amanda , Fitzgerald Cassandra , Baker Kimberlee , Stika Rachel , Linhares Daniel , Holtkamp Derald
Published: August 2023

Objective: To determine if the addition of a bench entry system in a commercial swine facility with a shower lowers the risk of personnel introducing environmental contamination. Materials and methods: Fluorescent powder was used to assess the bench entry system by simulating environmental contamination carried on the footwear of personnel entering a commercial swine farm. On each of ten days, four female employees entered the premises, stepped through the fluorescent powder, performed bench entry procedures, and showered into the farm. For ten additional replicates, the bench was removed and regular farm protocols were followed. The fluorescent powder contamination was evaluated with a grid system at four sampling points including before the bench, after the bench, before the shower, and after the shower. Statistical analysis was conducted to determine if there was a difference in the number of contaminated grid cells found at each sampling between the treatment groups. Results: Fluorescent powder was found after the shower on two study days in which the bench was removed but none when the bench was in place. There was a significant difference in contamination found directly after the bench between days with bench entry and days that the bench was removed, but this was not observed at any of the other sampling points. Implications: A bench entry system may decrease the risk that pathogens reach the clean side of the shower, but improved protocols and additional layers of biosecurity are needed.
Sow behavior and productivity in a small stable group-housing system
Authors: Campler Magnus , Pairis-Garcia Monique , Kieffer Justin , Moeller Steven
Published: August 2023

Objectives: To quantify behavior and productivity of females grouped in small static groups when fed using a single-entry/exit electronic sow feeder (ESF) over two consecutive gestation periods. Materials and methods: Fifty-eight gilts with no previous experience in group gestation housing were enrolled into 3, static, successive cohorts (Cohort 1, n = 20; Cohort 2, n = 18; and Cohort 3, n = 20) at day 35 of gestation. Pigs were housed individually throughout the farrowing period, and pigs that were healthy were moved back into their respective groups for their second gestation (Cohort 1, n = 19; Cohort 2, n = 13; Cohort 3, n = 17). Pig behavior, social rank, and post-gestation productivity was quantified for each gestation period. Results: Agonistic behaviors decreased between the first and second gestation (P < .001). High-ranked sows initiated more agonistic bouts around the ESF when compared to intermediate- and low-ranked sows (P < .001). Duration of active (P = .78) and inactive (P = .76) behaviors did not differ between gestation periods, but more active behaviors were observed near the ESF when compared to other areas of the pen (P < .001). High-ranked sows visited the feeder more frequently when compared to intermediate- and low-ranked sows (P < .001). No differences in subsequent litter or female productivity measures were found based on sow ranking. Implications: Housing gestating females in small static groups with an ESF decreased aggression between the first and second parity without detrimentally affecting general pig behavior or productivity.
A retrospective analysis of seasonal growth patterns of nursery and finishing pigs in commercial production
Authors: Wu Fangzhou , Liao Jingwen , Tokach Mike , Dritz Steve , Woodworth Jason , Goodband Robert , DeRouchey Joel , Vahl Christopher , Calderon-Cartagena Hilda , Van De Stoet Denise
Published: August 2023

Objective: Determine seasonal patterns of nursery and finisher growth performance in 3 commercial US production systems located in the midwest. Materials and methods: Five years of production records, including 5039 nursery and 5354 finisher production batches, were collected from 3 production systems. Explanatory variables include system, site, pig-flow type, feeder type, batch size, week of placement, average days-on-feed, fill length, number of sow farm sources, dietary energy, mortality, and initial body weight. Week of placement served as the unit for seasonal patterns. Nursery and finisher performance (average daily gain [ADG], average daily feed intake [ADFI], and gain to feed ratio [G:F]) were analyzed in separate datasets using multi-level linear mixed models. A guided stepwise selection approach was used to select fixed variables and their interactions. Seasonality curves were generated using rolling averages of least squares means with a 5-week window and 1-week step-size. Results: For nursery, the seasonality effect was significant (P < .001) for ADG, ADFI, but not for G:F. Nursery ADG and ADFI decreased as week of placement progressed from the 1st to 20th week of a year but increased thereafter. All finisher growth responses were affected by week of placement (P < .001) but the pattern and magnitude of seasonal variability differed among systems (system × week interactions, P < .02). Implications: Seasonal variability of nursery and finisher performance can be quantified using production records in a multi-level linear mixed model. Seasonality effects on finisher performance were system dependent, while nursery seasonality shared more similarity among investigated systems.
Pulmonary Paragonimus infection and other pathologic findings in feral swine (Sus scrofa) from Macon County, Alabama
Authors: Gilbreath Ebony , Gorham Sammy , Anderson Dennis , Witola William , Casimir Roslyn , Bridges Elvia , Gaston Wesson
Published: August 2023

Tuskegee University College of Veterinary Medicine (TUCVM) was integrated into a feral swine surveillance program to aid in monitoring feral swine in Macon County, Alabama. The program was initiated by the Wildlife Services division of the Animal Plant and Health Inspection Services of the United States Department of Agriculture. Feral swine were captured, humanely euthanized, and blood was collected for various serological analyses. The carcasses were then submitted to the TUCVM diagnostic laboratory for postmortem examination and tissues were collected for additional disease surveillance. This report highlights pathologic findings identified in 15 feral hogs captured from Macon County, Alabama between March 14, 2012 and April 16, 2013, and serves as a record of some of the diseases the feral swine in this area harbor. Some of the pertinent pathologic findings identified include pulmonary metastrongyliasis, pulmonary paragonimiasis and severe ectoparasitism.
Brownian Motion: A Financial Contradiction and Discontinuous Continuity Modeling
Authors: Madan Dilip
Published: August 2023

The assumption of continuity and randomness with its Brownian motion model is distinguished by having just one model for the local process evolution and that is the Brownian motion model. A continuous martingale is essentially a stochastic integral with respect to Brownian motion (Revuz and Yor, 1991; Chapter V). With just one model, the underlying assumptions come perilously close to being a contradiction. Formally, there is no contradiction but practically all anticipated diversity is excluded. By the time one reduces the universe of relevant models to a single entity it is clear that one has assumed or said too much. It is then likely that one has eliminated from consideration or contemplation many, if not all, financially relevant possibilities.
This paper investigates discrete or discontinuous approximations to continuity that are richer in their diversity of models and allow one to evaluate the financial relevance of the many choices that become possible. For the evaluation of financial relevance, attention is focused in the first instance on Sharpe ratios, recognizing that markets are unlikely to offer return possibilities at the extremes of zero or infinite Sharpe ratios. The Sharpe ratios typically seen for financial returns are, when positive, generally well below unity.
Sharpe ratios are but one measure of performance. Acceptability indices are an alternate arbitrage-consistent performance measure. The methodology for constructing acceptability indices is here generalized to the context of positive random variables to form an Attractiveness Index. Financial relevance is then additionally addressed using this Attractiveness Index. A richer collection of measures of performance can assist in dissecting and selecting economically relevant discontinuous alternatives to continuity modeling.
With a view towards assisting in the selection of discontinuous continuity approximations, one may relate Sharpe ratios and Attractiveness Indices observed in daily return data to their theoretical process counterparts. Using a simulation study, we build a neural net mapping from the daily data observations to the associated theoretical values.
Mac's Factor
Authors: Radley Milford
Published: August 2023

McLaren Artura Porsche 718 Spyder RS
Role of adjunctive nonpharmacological strategies for treatment of rapid-cycling bipolar disorder
Authors: Chakrabarti Subho , Jolly Amal J , Singh Pranshu , Yadhav Nidhi
Published: August 2023

Rapid-cycling bipolar disorder (RCBD) is a phase of bipolar disorder defined by the presence of ≥ 4 mood episodes in a year. It is a common phenomenon characterized by greater severity, a predominance of depression, higher levels of disability, and poorer overall outcomes. It is resistant to treatment by conventional pharmacotherapy. The existing literature underlines the scarcity of evidence and the gaps in knowledge about the optimal treatment strategies for RCBD. However, most reviews have considered only pharmacological treatment options for RCBD. Given the treatment-refractory nature of RCBD, nonpharmacological interventions could augment medications but have not been adequately examined. This review carried out an updated and comprehensive search for evidence regarding the role of nonpharmacological therapies as adjuncts to medications in RCBD. We identified 83 reviews and meta-analyses concerning the treatment of RCBD. Additionally, we found 42 reports on adjunctive nonpharmacological treatments in RCBD. Most of the evidence favoured concomitant electroconvulsive therapy as an acute and maintenance treatment. There was preliminary evidence to suggest that chronotherapeutic treatments can provide better outcomes when combined with medications. The research on adjunctive psychotherapy was particularly scarce but suggested that psychoeducation, cognitive behavioural therapy, family interventions, and supportive psychotherapy may be helpful. The overall quality of evidence was poor and suffered from several methodological shortcomings. There is a need for more methodologically sound research in this area, although clinicians can use the existing evidence to select and individualize nonpharmacological treatment options for better management of RCBD. Patient summaries are included to highlight some of the issues concerning the implementation of adjunctive nonpharmacological treatments.
Drug Recommendation based on Sentiment Analysis using ML
Authors: C N Vishwas
Published: August 2023

As e-commerce has grown, an increasing number of consumers prefer to buy drugs online for convenience's sake. As a result, the difficulties with health and medical diagnostics are becoming more well known. Because medical professionals write prescriptions based on their very limited experience, they frequently make drug mistakes. Technologies like data mining or recommender systems offer opportunities to investigate potential insight from diagnosis background records and aid physicians in reliably prescribing medications to reduce medication mistake. This effort aims to propose a medication recommendation system that can significantly lessen the workload of professionals. We create a system that, using ML classification algorithms, predicts whether a medicine can be taken or not based on the reviews. Key Words: Stress, Machine learning and IT professionals.
Does ESG Improve Firm Performance? Evidence from Indian Companies
Authors: Digar Biki
Published: August 2023

This research paper explores the association between ESG i.e.; Environmental, Social, and Governance factors, and the financial performance of 37 Indian companies. It shows how ESG financial execution influences the profitability of companies and its contributions toward sustainable development. It employs various regression models including pooled OLS, fixed effect, and random effect models as well as dynamic panel regression. This study results positively significant connection between ESG performance and firm performance in terms of capital efficiency. Return on Assets (ROA), Return on Equity (ROE) and Return on Capital Employed (ROCE) - these various financial metrics have demonstrated this positive connection. To support our findings this study employs both static and dynamic panel analysis. The insights of this paper are valuable for the stakeholders including policymakers, corporate managers, and investors who are interested in ESG principles and in understanding the relationship between ESG practices and companies financial performance. Key Words: ESG; Firm Performance; Sustainability; GMM Model.
El riesgo financiero como instrumento inherente en las actividades crediticias
Authors: Malla Alvarado Franklin Yovani , Salinas Rojas Lourdes Gabriela , Neira Paredes Andrea Judith , Rodríguez Armijos Carlos Alfredo
Published: August 2023

Introducción: En el Ecuador, el sector cooperativo ha tenido una aceptación favorable a través de los años, debido a que ha incluido en sus operaciones a sectores históricamente olvidados y que requerían del financiamiento para ejecutar sus emprendimientos e innovaciones, claro está, que este tipo de transacciones esta estrechamente vinculado al riesgo financiero de no poder recuperar la inversión y que las mismas ejerzan un efecto negativo en su estructura patrimonial.
Objetivo: Analizar la relación existente entre la morosidad con la liquidez y la rentabilidad de las Cooperativas de Ahorro y Crédito del segmento 3 de la provincia de Loja- Ecuador
Metodología: Se utiliza una metodología descriptiva correlacional y toma como base de datos las estadísticas que reposan en la página oficial de la Superintendencia de Economía Popular y Solidaria SEPS
Resultados: Se destaca que existe una relación directa entre las variables estudiadas del 0,55 (morosidad – liquidez) y 0,56 (morosidad – rentabilidad) respectivamente;  como futuras líneas de investigación se pueden determinar la relación entre morosidad y la cantidad de nuevos créditos otorgados.
Concluye en la necesidad de hacer este tipo de estudio con regularidad con el objeto de prever situaciones adversas que afecten la capacidad de seguir brindando el financiamiento que requieren las organizaciones en las economías emergentes.
Đánh giá hiện trạng và đề xuất một số giải pháp sử dụng bền vững tài nguyên thiên nhiên và nâng cao sinh kế cho người dân tại Vườn Quốc gia Phong Nha - Kẻ Bàng
Authors: Đồi Bùi Thế , Thể Trần Ngọc , Khang Lã Nguyên , Quyết Phan Thanh , Trí Võ Văn
Published: August 2023

Trên cơ sở nghiên cứu hiện trạng, bài báo đề xuất một số giải pháp sử dụng bền vững tài nguyên thiên nhiên (TNTN) và nâng cao sinh kế cho người dân tại khu Di sản Thiên nhiên Thế giới Vườn Quốc gia (VQG) Phong Nha - Kẻ Bàng (PN-KB). Số liệu và thông tin được thu thập thông qua phỏng vấn cán bộ VQG, chính quyền địa phương và người dân tại 13 xã vùng đệm. VQG PN-KB có diện tích rừng và đất lâm nghiệp lớn với là 124.832,55 ha; có tính đa dạng sinh học (ĐDSH) cao vào bậc nhất của Việt Nam; khu vực có 6 kiểu hệ sinh thái gồm: rừng trên núi đá vôi; rừng trên núi đất; hệ sinh thái hang động; sông ngầm; ao hồ và khe suối. Điều kiện KT-XH còn nhiều khó khăn, thách thức do kinh tế nông lâm nghiệp chậm phát triển; chất lượng nguồn nhân lực còn thiếu và yếu chưa đáp ứng nhu cầu phát triển KT-XH của địa phương; tỷ lệ hộ nghèo còn cao ở một số xã; chất lượng giáo dục, đào tạo và chăm sóc sức khỏe còn nhiều hạn chế. Công tác bảo vệ rừng có nhiều áp lực: hiện tượng khai thác gỗ và các loại lâm sản ngoài gỗ (LSNG) trái phép còn xảy ra; phát triển du lịch chưa bền vững. Một số giải pháp nhằm sử dụng bền vững TNTN nâng cao sinh kế người dân vùng đệm VQG PN-KB đã được đề xuất, gồm: (1) Giải pháp bảo vệ và sử dụng bền vững TNTN; (2) Giải pháp nâng cao sinh kế cho cộng đồng dân cư và (3) Giải pháp phát triển cộng đồng và bảo tồn, phát huy các giá trị văn hóa bản địa.
Đánh giá độ chính xác của các phương pháp phân loại thảm phủ dựa trên ảnh Sentinel-2 và Landsat 9
Authors: Huyền Mai Thị , Thế Phan Trọng , Lộc Phạm Thị
Published: August 2023

Nghiên cứu nhằm so sánh kết quả phân loại thảm phủ tại địa bàn huyện Trảng Bom, tỉnh Đồng Nai năm 2022 dựa trên ảnh vệ tinh Sentinel-2 và Landsat 9 bằng phương pháp Object Based Image Analysis (OBIA) và Maximum Likelihood Classification (MLC). Độ chính xác của kết quả phân loại ở mức cao và đáng tin cậy được thể hiện qua độ chính xác tổng thể (overall accuracy) đều trên 80% và hệ số Kappa từ 0,79 đến 0,88. Cụ thể độ chính xác tổng thể phân loại theo OBIA của ảnh Sentinel-2 và Landsat 9 là 91% và 86%, với hệ số Kappa lần lượt là 0,88 và 0,84, còn với phương pháp MLC của ảnh Sentinel-2 và Landsat 9 có độ chính xác tổng thể (overall accuracy) đạt 86% và 83%, hệ số Kappa lần lượt là 0,82 và 0,79. Kết quả nghiên cứu cho thấy phương pháp OBIA có nhiều ưu điểm và cho độ chính xác phân loại tốt hơn so với phương pháp MLC. Qua đó cũng cho thấy phương pháp OBIA sẽ phát huy hết ưu điểm nếu thực hiện trên ảnh vệ tinh có độ phân giải không gian cao. Qua kết quả phân loại ảnh cho thấy loại hình thực phủ trong khu vực nghiên cứu tại thời điểm 2022 chủ yếu là đất nông nghiệp (cây hằng năm và cây lâu năm), sau đó đến đất xây dựng, đất trống và cuối cùng là mặt nước.
Ước tính sinh khối trên mặt đất bằng viễn thám tích hợp và thuật toán học máy: nghiên cứu điểm tại Khu dự trữ sinh quyển miền Tây Nghệ An, Việt Nam
Authors: Nhung Đỗ Thị , Hùng Nguyễn Đình , Hải Phạm Ngọc , Phương Đặng Đỗ Lâm , My Nguyễn Thị Diễm , Mạnh Phạm Văn
Published: August 2023

Ước tính sinh khối trên mặt đất (AGB) từ dữ liệu viễn thám quang học và Radar khẩu độ tổng hợp (SAR) là một cách tiếp cận thiết thực để theo dõi chất lượng rừng tại khu dự trữ sinh quyển dài hạn. Sinh khối của rừng có ý nghĩa quan trọng thể hiện khả năng lưu trữ Carbon lớn và góp phần làm giảm biến đổi khí hậu toàn cầu. Nghiên cứu này trình bày phương pháp tích hợp dựa trên dữ liệu viễn thám đa nguồn và thuật toán học máy định lượng AGB và sự phân bố không gian của các kiểu rừng trong Khu dự trữ sinh quyển miền Tây Nghệ An, Việt Nam. Dữ liệu khảo sát thực địa năm 2022 được sử dụng với 169 ô mẫu được thu thập, trong đó 118 ô tham gia mô hình học máy để ước tính AGB và 51 ô còn lại được sử dụng để xác nhận kết quả. Hệ số xác định (R2), sai số bình phương trung bình (RMSE) và sai số trung bình tuyệt đối (MAE) được sử dụng để đánh giá và xác nhận hiệu suất của mô hình. Kết quả cho thấy cả 3 chỉ tiêu của mô hình đều tốt với RMSE và MAE có mức sai số dưới 30 Mg/ha và R2 khoảng 0,81 cho ước tính AGB. Nghiên cứu này cung cấp cái nhìn sâu sắc mới về mô hình ước tính AGB dựa trên công nghệ viễn thám đa nguồn cho rừng nhiệt đới tại Khu dự trữ sinh quyển thế giới thông qua phân tích toàn diện về dữ liệu viễn thám và mô hình học máy.
PR-317-10702-R01 Testing for the Dilation Strength of Salt
Authors: Brosnahan  , DeVries
Published: August 2023

A laboratory testing program on rock salt specimens was performed using test conditions that are consistent with the stresses that are experienced near the surfaces of salt caverns during storage operation. The proposed work effort focuses on improving the methodology for defining the onset of dilation for rock salt. Geomechanical studies use dilation criteria to assess the potential for salt damage that can lead to spalling in the cavern roof and/or walls and subsequent damage to the cavern or hanging string. This constraint is often the one that limits the minimum gas pressure in a natural gas storage cavern. This report documents the PRCI funded follow-on activities to the recently completed Gas Storage Technology Consortium project [DeVries, 2010]. The work activities completed include the following:

Laboratory dilation strength testing of eight specimens having preconditioning durations longer than 10 days.
Numerical modeling to identify and optimize an appropriate specimen shape for dilation testing in triaxial extension states of stress.
Laboratory constant mean stress extension testing on the optimized specimen shape.

DeVries [2010] documented the effects of the preconditioning durations on the dilation strength of salt specimens. Preconditioning of specimens is the process whereby specimens are subject to a relatively high hydrostatic stress for a specified period of time. It is believed that preconditioning mitigates some of the damage to the specimens induced by coring, transporting, and specimen preparation. The study documented by DeVries [2010] suggests that increasing the preconditioning duration increases the dilation strength of salt, with the maximum precondition duration limited to 10 days. This project expands upon these findings through additional testing to determine if preconditioning durations longer than 10 days has any additional benefit.

In addition to the preconditioning task, this study will also investigate the variability issues observed during dilation strength tests performed under triaxial extension states of stress. It is hypothesized that the high variability seen in extensional test results might be attributed to end effects caused by (1) the friction at the specimen-platen interface and (2) specimens breaking outside the range measured by gages. To help reduce frictional effects and breakage location issues, numerical models of alternate specimen shapes were created to provide a basis for testing a new specimen geometry. Laboratory tests were performed on the new specimen geometry to validate any of its possible benefits.
L20000 Pipetran Version IV - Program for the Simulation of Gas Pipeline Network Dynamics - Manual
Authors: Distefano
Published: August 2023

Every pipeline network is composed of combinations of some or all of the basic elements: pipeline segment; junction; compressor station; pressure regulator; storage field; flow boundary node; and pressure boundary node. While each element can affect the transient behavior of a pipeline network, the response of the system is quite different in each case. It is helpful to distinguish between these effects, and to characterize each element according to its ability to alter the dynamic response of a pipeline network.

A mathematical research program was conducted to study transient flow in gas transmission networks. The objective of the project was the development of mathematical models, computer techniques and computer programs to simulate the unsteady-state behavior of large gas pipeline networks.
PR-015-08605-R02 Assessment of Orifice Meter Flow Measurements with Low Differential Pressures
Authors: George  , Jowers  , Grimley
Published: August 2023

Measurement of natural gas flow with an orifice meter is a well-established methodology; however, orifice measurement accuracy is of concern when flow rates are low and the differential pressure (DP) across the orifice is at the extreme low end of common DP transmitter ranges. This research evaluated the performance of multiple types of transmitters in 10-inch and 4-inch orifice meter runs at differential pressures approaching 1 inch of water column (1� H2O), simulating low flow transmission meter stations and depleted production well stations. The results were analyzed to characterize and better understand the uncertainties and measurement errors associated with orifice meters operating with small bore diameters and low DPs. Transmitters tested included typical DP transmitters with stated accuracies of 0.1% of full scale, DP transmitters with stated accuracies as a percent of reading; and high-frequency-response DP transmitters. Data acquisition methods, transmitter technologies, and various calibrated measurement spans were studied for their potential to improve orifice meter accuracy at low DP conditions. This is an blinded report.
L51398 Causes of Failures of Defects that have Survived a Prior Hydrostatic Test
Authors: Kiefner  , Maxey  , Eiber
Published: August 2023

The observance in service or during hydrostatic testing of an occasional pressure reversal has raised a question as to what causes these reversals and what is their magnitude. A pressure reversal occurs when a defect survives a given pressure level only to fail at a lower pressure level upon subsequent pressurization from 0 pressure.

The objective of this study is to investigate the causes of pressure reversals and their magnitude. In addition, the probability of the occurrence of a pressure reversal was investigated along with the identification of the factors in hydrostatic testing that tend to eliminate or reduce the occurrence of pressure reversals.The causes and magnitudes of pressure reversals were studied in this investigation using a number of full-scale experiments on line pipe. The experiments involved artificially induced defects that were purposely subjected to several cycles of near failure load and various hold times. Also, the pressure testing experience on numerous pipelines and the documented associated pressure reversals have been factored into this investigation. The major factors defined as contributing to pressure reversals in line pipe of normal toughness are the subcritical (stable) crack growth during prior loading, the proximity of the defect to failure, and compressive yielding at the flaw tip during unloading. The maximumpressure reversal observed in normal toughness line pipe in the experiments was a 25.2 percent reduction from the previous pressure level as a leak. The maximum recorded service pressure reversal of 62 percent was for a rupture that occurred during testing of old low toughness line pipe.
L51563 SCC Resistance of Newly Developed Grade X70 and X80 Line Pipe Steels
Authors: Christman
Published: August 2023

The report describes the results of an evaluation of the stress-corrosion cracking (SCC) resistance of three high-strength, line pipe steels. These steels included an X70 grade containing Mn, V, and Cb, with a ferritic-bainitic microstructure; an X70 grade containing boron (B), with a bainitic structure; and a ferritic X80 grade microalloyed with Mo, Cb, V, and Ti. All three of these steels have been shown, in previous PRCI research programs, to have excellent strength, toughness, and resistance to hydrogen sulfide attack.
PR-389-114503-R01 Leak Prevention in CO2 Pipeline Valves and Launches By Correct Seal Material Selection
Authors: Lewan
Published: August 2023

Pipeline Research Council International, Inc. (PRCI) required guidelines for pipeline valve stem seals in CO2 rich applications such as for enhanced oil recovery (EOR) and carbon capture and storage (CCS). In particular, guidance was needed to ascertain when standard O-rings may be used, when a switch to rapid gas decompression (RGD) resistant O-rings is recommended and when O-rings should be replaced by more robust energized lip seals and/or by more robust seal materials. The guidelines would interface with both NORSOK M 710 Rev. 3 and ISO 23936-2, and give specific details on procedures, steps and decisions that have to be taken when attempting to qualify seals for dense phase CO2 use. In order to develop these guidelines, two well established sealing compounds having proven RGD resistance were selected for study, along with two materials which were not known for their RGD resistance. RGD testing was performed on housed O-rings of each compound using 4 different gas compositions that cover an appropriate range of field conditions for CO2 applications.
L51782 Guidelines for Weld Deposition Repair on Pipelines
Authors: Bruce
Published: August 2023

Pipeline repair by direct deposition of weld metal, or weld deposition repair, is an attractive alternative to the installation of full-encirclement sleeves for repair of wall loss on in-service pipelines. This is particularly true where the installation of full-encirclement sleeves is difficult or impossible, such as for wall loss in bend sections and fittings. The results of recently completed work at Edison Welding Institute and previous work by others has shown that weld deposition repairs have the ability to restore the static strength of a pipeline and are resistant to pressure cycles over a wide range of applications. Prior to the widespread use of this technique, it was necessary to establish guidelines for carrying out repairs using this technique These guidelines must address not only the welding issues, but issues pertaining to inspection following welding, acceptance standards for discontinuities detected during inspection, and other related issues

The objective of this project was to provide a report that contains theseguidelines. The guidance provided in this report is contained in two basic parts. The main body of the report contains a review of the various technological factors pertinent to weld deposition repair, Including a review of recently-completed research projects. The second part is an example guideline for carrying out weld deposition repair in the field, which was developed using the information contained in the main body of the report. This example guideline is in the form of a generic company specification and is contained in an appendix to the report.
L51737 Development of Modeling Procedures for Branch Welds
Authors: Kirk
Published: August 2023

One major difficulty in developing fitness-for-purpose based flaw acceptance criteria for pipeline branch connections is the calculation of the stress distributions in the vicinity of the welds. Even with the latest computer-aided modelling technologies, finite element modeling of branch connections using three-dimensional (3-D) solid elements is the only way to accurately determine the stress distributions local to the weld toes of branch connections.

This report describes work to access the applicability of linear elastic fracture mechanics (LEFM) principles to a saddle-pad reinforced branch connection modelled using 3-D elements, The effort concentrated on determining the amount and location of plastic zones resulting from different combinations of service loadings. Loadings considered include pressurization to 72% of the specified minimum yield strength with the addition of main pipe end tension or compression. The effect of contact and different material models were also quantified.
L51559 Factors Affecting Pipe Collapse Phase II
Authors: Kyriakides
Published: August 2023

Offshore pipelines installed in moderate to deep water depths (1,500 ft. and beyond) must, by necessity, be designed to withstand ambient external pressure. Improper design can lead to catastrophic collapse of large sections of the structure. During the installation process the line can experience significant bending and tension loads in addition to external pressure. These additional loads can significantly reduce the collapse pressure of the pipe.

Special purpose combined loading test facilities were designed and built in which pressures equivalent to 10,000 ft. and beyond were simulated. The test facilities were used to establish load interaction collapse envelopes for the two types of combined loading mentioned. Bending/pressure collapse envelopes were generated for tubes with diameter to thickness ratios of 34.7, 24.5, 18.2 and 17.3. Tension/pressure collapse envelopes were generated for tubes with diameter to thickness ratios of 38.3, 24.5, 18.2 and 12.2. The geometric imperfections and material parameters were recorded for all test specimen's prior to collapse. Under bending/pressure loading the tube response, the critical collapse loads and the nature of the instabilities observed were found to depend on the loading path. Collapse was found to be relatively insensitive to the history for tension/pressure loading.
L51806 Effects of Hydrogen on Low-pH Stress Corrosion Crack Growth
Authors: Parkins
Published: August 2023

There is circumstantial evidence of hydrogen playing a role in, so called, low pH SCC of pipeline steel, but direct evidence for such is lacking. Resolution of this situation is of practical importance because of its implications for modeling. Thus, existing models for high pH SCC of pipelines are based upon a dissolution controlled mechanism of crack growth, but such models will not be applicable to low pH SCC if hydrogen is involved with the latter.

Measurements have been made of the permeation of hydrogen into X52 and X60 pipeline steels at various potetials while exposed to a simulated ground water containing different amounts of carbon dioxide, related to the conditions thought to be associated with transgranular stress corrosion cracking of pipelines. As a consequence of these measurements it is now known unequivocally that hydrogen enters the steel for all such solutions over wide ranges of potential, including those most likely involved in the cracking of pipelines, and with such entry enhanced as the amount of carbon dioxide present in the solution increased. For a given set of environmental conditions, it was found that films on the surface of the pipe, such as may exist in service conditions, could hinder, but not prevent, the ingress of hydrogen. Hydrogen in steel is usually regarded as being trapped at dislocations, grain boundaries or interfaces between the matrix and second phase particles and measurements relating to such indicate that the X60 steel contains appreciably fewer traps than the X52 steel for equivalent charging conditions. However, the trapped hydrogen was found to have no significant influence on the ductility of the steels when subsequently tested in air, although the ductility was impaired by thxe continued ingress of hydrogen when equivalent tests were conducted in the presence of the charging solution. No convincing evidence has been obtained for the ingress of hydrogen into the steels facilitating the early stages of plasticity under exposure conditions relating to those involved in low pH stress corrossion cracking. The most probable mechanism of stress corrosion crack growth in pipeline steel in the solutions studied and at potentials likely to obtain in service involves both dissolution and hydrogen ingress to the steel, although the interactions of those two factors in the fracture process remain speculative.
L52236 Ultrasonic Inspection of Hot Tap Branch Connections and Weld Sleeve-Fillet Weld using Phased Arrays
Authors: Lozev Mark , Spencer Roger , Huang Ta-Chieh , Patel Pratik
Published: August 2023

This evaluatates the emerging phased-array (PA) automated ultrasonic testing (AUT) method and further assesses the performance of AUT and PA AUT techniques to detect and size flaws in the current pipelines with a relatively wide range of wall thickness.

Given the critical nature of pipelines and the consequences of structural failure, designers are adopting reliability and fitness-for-purpose (FFP) design methods to ensure that structural integrity can be guaranteed throughout the entire design life. The use of reliability and FFP based design methods requires the use of improved assessment and inspection techniques that can reliably detect and size fabrication flaws produced during construction and repair. Over the last five years, AUT has been used increasingly in cross-country and offshore pipeline construction to improve defect detection and sizing reliability. AUT inspection offers many advantages over conventional manual UT including:

- Improved reliability and performance (defect detection and sizing)

- Ability to obtain an electronic copy of inspection results

- Increased speed.
L51990 Extended Model for Pipe Soil Interaction
Authors: Honegger
Published: August 2023

This program contributes to maintaining and improving the integrity and safety of existing pipelines with regard to ground movement hazards, and reducing the capital costs of new pipeline systems. The research program focused on the axial, lateral and complex loading of pipeline due to soil movements. It includes (1) a literature review: it presents significant issues related to modeling pipe-soil interaction with a focus to recent development since ASCE (1984); (2) axial loading: it includes a summary of the methods to estimate the axial soil forces on pipeline and recent field measurements on decommissioned pipe sections in weak to desiccated, cohesive to sandy silts in California; (3) lateral loading of buried pipeline: it covers the effects of cover depth, soil strength, loading rate, trench geometry and backfill strength on pipe-soil interaction; (4) complex loading of buried pipeline: the interaction between the lateral and axial soil forces on pipeline are studied; and (5) quantification of mitigative methods: a physical testing program including a total of 20 laterally loaded pipelines are used to identify and quantify the effects of various mitigative methods on reducing lateral loads transferred to a buried pipeline.
PR-343-06605-R02 USM Recalibration Frequency
Authors: Hall  , Zanker  , Kelner
Published: August 2023

This program is intended to improve the understanding of the stability over time of gas multi-path ultrasonic flow meters (USMs). Within the Natural Gas Industry, there are currently on universal standards requiring periodic recalibration of USMs. Removing these flow meters from serviced for recalibration is costly and inconvenient. However, the primary reason that a recalibration standard does not exist is the lack of definitive data regarding the long-term stability of installed USMs. In order to address this situation, collection and analysis of data was performed to help formulate a recalibration guideline. Specific tasks include: (1) review and utilization of existing published technical papers, (2) working with certified flow calibration facilities to obtain data, (3) obtaining data from USM manufactures on changing of electronics and/or transducers, (4) obtaining historical recalibration data, and (5) participation in selected recalibrations by PRCI member companies.
L51684 Assessing the Strength of Corroded Elbows
Authors: Bubenik  , Rosenfeld
Published: August 2023

Corrosion affects tees and elbows as well as straight pipe. The effect of metal-loss corrosion on the remaining strength of straight pipe can be predicted using ASME B31G, ANSI/ASME B31G Manual for Determining the Remaining Strength of Corroded Pipelines.\ Modifications to the B31G methodology to account for the defect profile have changed its accuracy for straight pipe. These techniques have been successfully used by pipeline operators for several years to assess whether corrosion damage to a pipeline warrants repair or replacement or whether it may be safely left in service.The B31G method does not address corroded tees and elbows
L51770 Compressor Station Maintenance Cost Analysis
Authors: Smalley  , Mauney  , Ash
Published: August 2023

A comprehensive study of compressor maintenance data including capital and expense to identify the drivers for optimizing maintenance cost expenditures. Anonymous company comparisons which allow individual companies to compare their maintenance expenses to others in the industry, using various methods of normalization. Correlations by linear regression to characterize relationships between expense and various measures of size (deliveries, installed horsepower, horsepower hours, miles/KM of pipeline, capital value, number of units).

This report provides information on the maintenance of compressors for gas transmission. It starts with a survey designed to characterize the pipeline industry's practice in managing maintenance and recording maintenance data; to gather hard data on maintenance expense and its drivers; and identifies opportunities to optimize maintenance expenditures. The report describes the survey and the goal of each question, then presents the results, which include data on consistency of FERC Form 2 filing practices, availability of hard data, distribution of expenses, budgeting and decision making practices. The assembled responses also include a list of practices which individual companies perceive as unique or especially beneficial; a list of perceived opportunities for controlling or optimizing maintenance and perceived needs for research, products, data, and tools to support future maintenance optimization. Results include regression coefficients and standard errors (which help characterize the relationship), and the inferred slope with its own standard error (which helps quantify the dependence of the expense on these various independent variables). These correlations have included available data for combined O and M and fuel use as expenses.

This study conducted over numerous years has assembled a number of valuable databases, and the report describes these and the use which the project has made of them. The report also provides various analyses and presentation of maintenance information based on detailed analysis of these data bases. Analysis of company totals, maintenance for individual compressor stations, for individual units, or for different models within the systems of individual companies. A final analysis and supporting documentation is provided that applies data from FERC filings for combined O and M, fuel use and fuel or power cost by station.