Single Farm Research Articles

Analysis and comparison of turbulence models on wind turbine performance using SCADA data and machine learning technique

Wind energy has grown significantly over the last decade. With this, various improvements in the design of the wind turbine are geared towards increasing the reliability of several components. Wind turbulence has a huge effect on the fatigue loading of wind turbines considered in the design. Several monitoring methodologies, such as turbulence intensity analysis, are used to identify wind turbulence. In this paper, a method based on machine learning techniques and data from Supervisory Control and Data Acquisition (SCADA) systems is described. Five machine learning models are generated and compared in this study with the use of the operational data from the SCADA of wind turbines in a single wind farm. Results showed that the model based on Linear Regression in terms of a quadratic hyperparameter has lesser errors compared to the other models that were generated. Each parameter used in the creation of the model affects its performance. Observations in the nacelle system also showed higher errors due to the relationship between rotor speed and the blade angle. The rotor performance is mostly influenced by wind turbulence as the variation in wind speeds and rotational speeds have a certain correlation. Based on the results, it can be concluded that the use of SCADA data in generating turbulence models provides key insights into the relation of the turbulence intensity to the various components. It can be used as the basis for developing turbulence monitoring models that could help improve the design and operation of wind turbines.

Highly pathogenic avian influenza A(H5N1) virus infection in farmed minks, Spain, October 2022.

In October 2022, an outbreak in Europe of highly pathogenic avian influenza (HPAI) A(H5N1) in intensively farmed minks occurred in northwest Spain. A single mink farm hosting more than 50,000 minks was involved. The identified viruses belong to clade 2.3.4.4b, which is responsible of the ongoing epizootic in Europe. An uncommon mutation (T271A) in the PB2 gene with potential public health implications was found. Our investigations indicate onward mink transmission of the virus may have occurred in the affected farm.

Epidemiological Analysis on the Occurrence of Salmonella enterica Subspecies enterica Serovar Dublin in the German Federal State Schleswig-Holstein Using Whole-Genome Sequencing.

The cattle-adapted serovar Salmonella Dublin (S. Dublin) causes enteritis and systemic diseases in animals. In the German federal state Schleswig-Holstein, S. Dublin is the most important serovar in cattle indicating an endemic character of the infection. To gain information on dissemination and routes of infection, whole-genome sequencing (WGS) was used to explore the genetic traits of 78 S. Dublin strains collected over a period of six years. The phylogeny was analysed using core-genome single nucleotide polymorphisms (cgSNPs). Genomic clusters at 100, 15 and 1 cgSNPs were selected for molecular analysis. Important specific virulence determinants were detected in all strains but multidrug resistance in S. Dublin organisms was not found. Using 15 cgSNPs epidemiological links between herds were identified, clusters at 1 cgSNPs provided clear evidence on both persistence of S. Dublin at single farms in consecutive years and transmission of the organisms between herds in different distances. A possible risk factor for the repeated occurrence of S. Dublin in certain districts of Schleswig-Holstein might be the spreading of manure on pastures and grassland. Effective control of S. Dublin requires farm-specific analysis of the management supplemented by WGS of outbreak causing S. Dublin strains to clearly identify routes of infection.

Mathematical modeling in the agro-industrial complex: basic problems and models construction

Currently, information technologies have been tightly integrated into agriculture. Since no computer calculations are possible without a powerful mathematical apparatus, the question arises about the possibility of modeling the processes occurring in agriculture with the help of modern achievements of science and technology. The present study is devoted to the existing methods of mathematical modeling in agriculture in relation to the applied aspects of agriculture. The aim of the research is to develop a critical approach to modern developments in the field of mathematical modeling and their place in agriculture. It is shown that the introduction of mathematical models based on modern scientific knowledge contributes to the optimization of agricultural processes and increasing the efficiency of any farm. Based on statistical studies, it is shown that among all branches of agriculture, mathematical methods are most often used in economic calculations, least of all, in calculations related to farm modeling. This is explained both by the complexity of modeling all processes occurring within a single farm, and by the loss of accuracy, which increases with the complexity of the system model.

Evaluating natural planned exposure protocols on rotavirus shedding patterns in gilts and the impact on their suckling pigs

Objective: The objectives of this study were to determine the pattern of rotavirus A (RVA), rotavirus B (RVB), and rotavirus C (RVC) shedding in gilts after natural planned exposure (NPE) administration and assess the effects on piglet weaning weight, preweaning mortality, and RV shedding. Materials and methods: A total of 70 pregnant gilts were enrolled and allocated into 4 groups. Group 1 was given NPE at 5, 4, and 3 weeks prefarrowing (WPF); Group 2 at 5 and 3 WPF; and Group 3 at 5 WPF only. Group 4 (control group) did not receive any NPE. Samples from 46 gilts and litters (5 piglets/litter) were tested at 12 sample times. Piglets were sampled weekly from 24 hours of age until 6 weeks of age and tested by quantitative reverse transcriptase-polymerase chain reaction for RVA, RVB, and RVC. Results: There was a significant improvement in weaning weight of piglets born to gilts that received 3 NPE administrations compared to fewer or no NPE administrations. Shedding of RVA and RVB from piglets were well controlled in the farrowing room regardless of treatment group, but RVC was observed as early as 1 week old. This study was conducted on a single farm, and the results should be carefully interpreted with knowledge of variations in farms and systems. Implications: Three administrations of NPE to gilts prefarrowing had valuable production and economic benefits for the producer. Circulation patterns of RVA, RVB, and RVC appear to correlate; interventions for one have value against the others.

Effects of Digitalization and Intangible Assets in the Crop Production Sector

In economic research, the introduction of digital innovations in agriculture is identified as a critical factor for changing business models in terms of creating economies of scale, improving productivity and efficiency within a single farm, and creating and capturing value in the agricultural sector. The present study attempts, on the one hand, to systematize the effects of digitalization processes in relation to the crop sector from available research. On the other hand, it analyses empirical data of crop farms through the lens of digital transformation. An econometric analysis was carried out, using data from enterprises from the crop growing sector that carry out costs related to innovation activities. The scope of the study covers a period of five years.

Reckoning the implementation of paddle operated single roll farm yard manure applicator under protected cultivation

Reckoning the implementation of paddle operated single roll farm yard manure applicator under protected cultivation

Active Power Cooperative Control for Wind Power Clusters with Multiple Temporal and Spatial Scales

To improve the control of active power in wind power clusters, an active power hierarchical predictive control method with multiple temporal and spatial scales is proposed. First, the method from the spatial scale divides the wind power clusters into the cluster control layer, sub-cluster coordination layer and single wind farm power regulation layer. Simultaneously, from the temporal scale, the predicted data are divided layer by layer: the 15 min power prediction is deployed for the first layer; the 5 min power prediction is employed for the second layer; the 1 min power prediction is adopted for the third layer. Secondly, the prediction model was developed, and each hierarchical prediction was optimized using MPC. Thirdly, wind farms are dynamically clustered, and then the output power priority of wind farms is established. In addition, the active power of each wind farm is controlled according to the error between the dispatch value and the real-time power with feedback correction so that each wind farm achieves cooperative control with optimal power output. Finally, combined with the simulation of practical wind power clusters, the results show that the wind abandonment rate was reduced by 2.13%, and the dispatch of the blindness was overcome compared with the fixed proportional strategy. Therefore, this method can improve the efficiency of cooperative power generation.

Occurrence of mcr-1 and mcr-2 colistin resistance genes in porcine Escherichia coli isolates (2010-2020) and genomic characterization of mcr-2-positive E. coli.

The global emergence of plasmid-mediated colistin resistance is threatening the efficacy of colistin as one of the last treatment options against multi-drug resistant Gram-negative bacteria. To date, ten mcr-genes (mcr-1 to mcr-10) were reported. While mcr-1 has disseminated globally, the occurrence of mcr-2 was reported scarcely. We determined the occurrence of mcr-1 and mcr-2 genes among Escherichia coli isolates from swine and performed detailed genomic characterization of mcr-2-positive strains. In the years 2010-2017, 7,614 porcine E. coli isolates were obtained from fecal swine samples in Europe and isolates carrying at least one of the virulence associated genes predicting Shiga toxin producing E. coli (STEC), enterotoxigenic E. coli (ETEC) or enteropathogenic E. coli (EPEC) were stored. 793 (10.4%) of these isolates carried the mcr-1 gene. Of 1,477 additional E. coli isolates obtained from sheep blood agar containing 4 mg/L colistin between 2018 and 2020, 36 (2.4%) isolates were mcr-1-positive. In contrast to mcr-1, the mcr-2 gene occurred at a very low frequency (0.13%) among the overall 9,091 isolates. Most mcr-2-positive isolates originated from Belgium (n = 9), one from Spain and two from Germany. They were obtained from six different farms and revealed multilocus sequence types ST10, ST29, ST93, ST100, ST3057 and ST5786. While the originally described mcr-2.1 was predominant, we also detected a new mcr-2 variant in two isolates from Belgium, which was termed mcr-2.8. MCR-2 isolates were mostly classified as ETEC or ETEC-like, while one isolate from Spain represented an atypical enteropathogenic E. coli (aEPEC; eae+). The ST29-aEPEC isolate carried mcr-2 on the chromosome. Another eight isolates carried their mcr-2 gene on IncX4 plasmids that resembled the pKP37-BE MCR-2 plasmid originally described in Belgium in 2015. Three ST100 E. coli isolates from a single farm in Belgium carried the mcr-2.1 gene on a 47-kb self-transmissible IncP type plasmid of a new IncP-1 clade. This is the first report of mcr-2 genes in E. coli isolates from Germany. The detection of a new mcr-2 allele and a novel plasmid backbone suggests the presence of so far undetected mcr-2 variants and mobilizable vehicles.

Flood Damage on Dairy Farms: A What-If Analysis to Assess Economic Losses

Although the impact of floods on the agricultural sector is relevant, with potential consequences on food security, in the new EU Common Agricultural Policy (CAP) proposal, agricultural risk management tools have been reinforced and extended. As far as we know, guidelines for the estimation of insurance indemnities related to flooding damage in the European livestock sector have not been proposed yet, unlike what has occurred in extra-European contexts. The present research proposes a model to identify the components of flood damage on dairy farms aimed at categorizing the cost typologies related to flood events by implementing a what-if approach. Our results highlight that collecting data about the vulnerability of a farm is an essential condition to assess the severity of damage from an economic perspective. In fact, even if some of the variables considered cause large economic losses per se, others are mainly related to poor management of issues related to the health of the herd (i.e., mastitis, lameness, other diseases). Such issues can be exacerbated by floods. Herd management, which includes comprehensive data collection, is essential for the calculation of economic losses in a single farm case and is also indispensable for the calculation of indemnity for the recovery of farming activities.

How to foster changes towards farm sustainability?: learning outcomes from a co-innovation project on vegetable-beef cattle family farms in Uruguay

Current global challenges for family farmers, such as the deterioration of arable land and low family income, cannot be addressed only by working on single farm components. Improving the sustainability of family farms requires a multi-objective systems approach and may be seen as an evolutionary process composed of iterative learning cycles. We developed a co-innovation project from 2014 to 2017 that involved characterisation, diagnosis, redesign, and implementation and evaluation of the redesigns on farms. Low family income, low labour productivity and the deterioration of soil quality were the main problems impacting farm sustainability. We identified crop management factors and soil fertility deficiencies as the main causes of low yields. After three cycles of diagnosis, redesign, implementation and monitoring, the average family income increased by 32%, labour productivity increased by 22%, and all the farms implemented soil erosion control measurements. Greater implementation of the farm redesign plans resulted in greater improvements in family income, labour productivity, and crop yields. We identified four types of activities that supported learning throughout the co-innovation process: regular farm visits; meetings to discuss diagnosis, planning and evaluation; field days, and reflection workshops. The strategic use of system analysis tools to promote learning eased communication among different actors, allowing shared learning.

SARS-CoV-2 Monitoring on Mink Farms in Poland.

Many countries have reported severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infections in mink, and transmission back to humans has raised the concern of novel variants emerging in these animals. The monitoring system on Polish mink farms detected SARS-CoV-2 infection first in January 2021 and has been kept in place since then. Oral swab samples collected between February 2021 and March 2022 from 11,853 mink from 594 farms in different regions of Poland were screened molecularly for SARS-CoV-2. Isolates from those with the highest loads of viral genetic material from positive farms were sequenced and phylogenetically analysed. Serological studies were also carried out for one positive farm in order to follow the antibody response after infection. SARS-CoV-2 RNA was detected in mink on 11 farms in 8 out of 16 Polish administrative regions. Whole genome sequences were obtained for 19 SARS-CoV-2 strains from 10 out of 11 positive farms. These genomes belonged to four different variants of concern (VOC) - VOC-Gamma (20B), VOC-Delta (21J), VOC-Alpha (20I) and VOC-Omicron (21L) - and seven different Pango lineages - B.1.1.464, B.1.1.7, AY.43, AY.122, AY.126, B.1.617.2 and BA.2. One of the nucleotide and amino acid mutations specific for persistent strains found in the analysed samples was the Y453F host adaptation mutation. Serological testing of blood samples revealed a high rate of seroprevalence on the single mink farm studied. Farmed mink are highly susceptible to infection with SARS-CoV-2 of different lineages, including Omicron BA.2 VOC. As these infections were asymptomatic, mink may become an unnoticeable virus reservoir generating new variants potentially threatening human health. Therefore, real-time monitoring of mink is extremely important in the context of the One Health approach.

Epidemiological investigation and genetic evolutionary analysis of PRRSV-1 on a pig farm in China.

Porcine reproductive and respiratory syndrome virus (PRRSV) has brought serious economic losses to pig industry. PRRSV-1 have existed in China for more than 25 years. The prevalence and features of PRRSV-1 on Chinese farms are unclear. We continuously monitored PRRSV in a pig farm with strict biosafety measures in Henan Province, China, in 2020. The results showed that multiple types of PRRSV coexisted on this single pig farm. PRRSV-1 was one of the main circulating strains on the farm and was responsible for infections throughout nearly the entire epidemic cycle. Phylogenetic analysis showed that PRRSV-1 isolates from this pig farm formed an independent branch, with all isolates belonging to BJEU06-1-like PRRSV. The analysis of selection pressure on ORF5 on this branch identified 5 amino acids as positive selection sites, indicating that PRRSV-1 had undergone adaptive evolution on this farm. According to the analysis of ORF5 of PRRSV-1 on this farm, the evolutionary rate of the BJEU06-1-like branch was estimated to be 1.01 × 10-2 substitutions/site/year. To further understand the genome-wide characteristics of PRRSV-1 on this pig farm, two full-length PRRSV-1 genomes representative of pig farms were obtained. The results of amino acid alignment revealed that although one NSP2 deletion was consistent with BJEU06-1, different new features were found in ORF3 and ORF4. According to the above results, PRRSV-1 has undergone considerable evolution in China. This study is the first to report the prevalence and characteristics of PRRSV-1 on a large farm in mainland China, which will provide a reference for the identification and further prevention and control of PRRSV-1.

Mortality and culling of adult dairy cows in Jordan: A 3-year study (2016-2018) based on a single intensively managed dairy farm.

Dairy cow mortality and culling are important parameters reflecting on cow health, productivity, and welfare as well as important determinants of herd sustainability, growth, and profitability. There are no published reports on the causes and rates of mortality and culling of dairy cows in Jordan. Therefore, the objectives of this study were to determine the most common causes and rates of mortality and culling of adult dairy cows in Jordan using a single well-managed dairy farm as a model over 3 years. Data extracted from the farm management record software over 3 years (January 2016-December 2018) were used in this study. Cow-specific data included the date and month of sale, death or euthanasia, age, parity, reproductive status, and daily milk yield. Cow health-specific data included physical examination findings, presumptive diagnosis, medical or surgical treatments, postmortem findings, and any available laboratory findings. Descriptive analysis was performed to determine means (± standard deviation) and frequencies of various variables using Excel Spreadsheets of Microsoft Word 10. The 3-year rolling cow population in the farm used in the study was 500 ± 35. The overall mortality and culling rates were 5.9% and 28.5%, respectively. The mean age of died and culled cows was 3 ± 1.2 and 4 ± 1.5 years, respectively. The mortality rates were highest in the colder months (January through April). The most frequent causes of mortality were infectious diseases (28%), followed by non-infectious gastrointestinal diseases (25%), udder and teat diseases (mastitis 22%), and other diseases/accidents (25%). Of the infectious diseases, the most frequently diagnosed were enterotoxemia (12%), tuberculosis (TB) (8%), enteric salmonellosis (7%), and paratuberculosis (1%). The most frequently diagnosed non-infectious gastrointestinal diseases were traumatic reticulitis (11%), vagal indigestion (9%), and abomasal ulcer (5%). The most frequently diagnosed diseases causing mortality involving other body systems were reproductive diseases (acute puerperal metritis 6%), respiratory diseases (pneumonia 5% and pulmonary embolism 1%), metabolic diseases (fatty liver 3%), musculoskeletal diseases (septic arthritis 3% and downer cow syndrome 4%), neurologic diseases (unspecified causes 2%), and finally accidents (electrocution 1%). The most frequent causes of culling were old age/low milk production (39%), followed by the poor reproductive performance (31%), diseases/accidents (24%), and unidentified causes (6%). The most frequent diseases/accidents causing culling were udder diseases (mastitis 32%), followed by non-infectious gastrointestinal diseases (28%) (vagal indigestion [15%], rumen tympany [7%], and abomasal ulcer [6%]), musculoskeletal diseases (23%) (foot and claw diseases [7%], downer cow syndrome [7%], hip luxation [5%], septic arthritis [2%], and gastrocnemius rupture [2%]), respiratory diseases (pneumonia 10%), and finally infectious diseases (9%) (paratuberculosis [3%], hemorrhagic bowel syndrome [2%], and TB [2%]). Results of this study showed that the majority of deaths and culling of dairy cows in Jordan are due to infectious diseases followed by non-infectious gastrointestinal diseases and mastitis. More efforts aiming at improving biosecurity standards, nutritional management, and mastitis prevention measures are required to limit the impact of disease on farm economy, animal health and productivity, and animal welfare in Jordan.

Modelling the field personnel resources to control foot-and-mouth disease outbreaks in New Zealand.

The objective of the study was to simulate New Zealand's foot-and-mouth disease (FMD) operational plan to determine personnel requirements for an FMD response and understand how the numbers of front-line staff available could affect the size and duration of FMD outbreaks, when using stamping-out (SO) measures with or without vaccination. The model utilized a national dataset of all known livestock farms. Each simulation randomly seeded infection into a single farm. Transmission mechanisms included direct and indirect contacts, local and airborne spread. Prior to each simulation, the numbers of personnel available for front-line tasks (including contact tracing, surveillance of at-risk farms, depopulation and vaccination) were set randomly. In a random subset of simulations, vaccination was allowed to be deployed as an adjunct to SO. The effects of personnel numbers on the size and duration of epidemics were explored using machine learning methods. In the second stage of the study, using a subset of iterations where numbers of personnel were unconstrained, the number of personnel used each day were quantified. When personnel resources were unconstrained, the 95th percentile and maximum number of infected places (IPs) were 78 and 462, respectively, and the 95th percentile and maximum duration were 69 and 217 days, respectively. However, severe constraints on personnel resources allowed some outbreaks to exceed the size of the UK 2001 FMD epidemic which had 2026 IPs. The number of veterinarians available had a major influence on the size and duration of outbreaks, whereas the availability of other personnel types did not. A shortage of veterinarians was associated with an increase in time to detect and depopulate IPs, allowing for continued transmission. Emergency vaccination placed a short-term demand for additional staff at the start of the vaccination programme, but the overall number of person days used was similar to SO-only strategies. This study determined the optimal numbers of front-line personnel required to implement the current operational plans to support an FMD response in New Zealand. A shortage of veterinarians was identified as the most influential factor to impact disease control outcomes. Emergency vaccination led to earlier control of FMD outbreaks but at the cost of a short-term spike in demand for personnel. In conclusion, a successful response needs to have access to sufficient personnel, particularly veterinarians, trained in response roles and available at short notice.

Characterization of Staphylococcus aureus Isolates from Bovine Mastitis and Bulk Tank Milk: First Isolation of Methicillin-Susceptible Staphylococcus aureus in Japan.

Staphylococcus aureus is one of the most important pathogens in humans as well as in livestock. Particularly, bovine mastitis caused by S. aureus is a serious issue in dairy farms due to disease recurrence. Here, cases of S. aureus-mediated intramammary infection occurring in the Miyagi Prefecture in Japan were monitored from May 2015 to August 2019; a total of 59 strains (49 from bovine milk and 10 from bulk milk) were obtained from 15 dairy farms and analyzed via sequence-based typing methods and antibiotic susceptibility tests. Two pairs of isolates were determined as recurrence cases from the same cows in distinct farms. The sequence type (ST), spa type, and coa type of each pair were the same: one pair showed ST705, t529, and VIb and the other showed ST352, t267, and VIc. In addition, the possession of toxin genes analyzed of each pair was exactly the same. Furthermore, seven oxacillin-sensitive clonal complex 398 isolates were obtained from a single farm. This is the first confirmed case of a Methicillin-Sensitive SA (MSSA) ST398 strain isolated from mastitis-containing cows in Japan. Our findings suggest that nationwide surveillance of the distribution of ST398 strains in dairy farms is important for managing human and animal health.

Assessing Genetic Diversity and Searching for Selection Signatures by Comparison between the Indigenous Livni and Duroc Breeds in Local Livestock of the Central Region of Russia

Indigenous pig breeds are mainly associated with the adaptive capacity that is necessary to respond adequately to climate change, food security, and livelihood needs, and natural resources conservation. Livni pigs are an indigenous fat-type breed farmed in a single farm in the Orel region and located in the Central European part of the Russian Federation. To determine the genomic regions and genes that are affected by artificial selection, we conducted the comparative study of two pig breeds with different breeding histories and breeding objectives, i.e., the native fat-type Livni and meat-type Duroc breeds using the Porcine GGP HD BeadChip, which contains ~80,000 SNPs. To check the Livni pigs for possible admixture, the Landrace and the Large White breeds were included into the study of genetic diversity as these breeds participated in the formation of the Livni pigs. We observed the highest level of genetic diversity in Livni pigs compared to commercial breeds (UHE = 0.409 vs. 0.319–0.359, p < 0.001; AR = 1.995 vs. 1.894–1.964, p < 0.001). A slight excess of heterozygotes was found in all of the breeds. We identified 291 candidate genes, which were localized within the regions under putative selection, including 22 and 228 genes, which were specific for Livni and Duroc breeds, respectively, and 41 genes common for both breeds. A detailed analysis of the molecular functions identified the genes, which were related to the formation of meat and fat traits, and adaptation to environmental stress, including extreme temperatures, which were different between breeds. Our research results are useful for conservation and sustainable breeding of Livni breed, which shows a high level of genetic diversity. This makes Livni one of the valuable national pig genetic resources.

PSXI-17 Evaluation of Influence of the Total Accumulation of Toxic Elements in Blood Serum on the Indicators of Milk Productivity of the Holstein Cows

Abstract The main objective was to study the milk productivity of lactating cows depending on the level of total accumulation of toxic metals in the blood serum. The experimental part of work was carried out on clinically healthy Holstein cows (n=45; lactation stage - 20-40 days after calving) bred in a single farm. The elemental composition of blood serum was studied for 4 chemical elements (Al, Pb, Sn, Sr) by ICP AES and ICP MS. The indicators of milk productivity of cows were evaluated by the yield of milk fat, protein, lactose, dry matter, SOMO and the average daily milk yield. To assess the magnitude of the toxic load on the body of cows, the coefficient of the total toxic load Ktox (µg/ml) was calculated. To calculate the coefficient, the sum of the concentrations of some toxic elements in the blood serum was used: Ktox=Al+Pb+Sn+Sr. Based on the data on the value of the total toxic load coefficient Ktox in blood serum, three groups were formed: group I included cows with a minimum value of the toxic load coefficient (Ktox=0.128 (0.088-0.142) μg/ml relative to the study sample; group II with an average (Ktox=0.229 (0.206-0.276) µg/ml; Group III included cows with the maximum coefficient (Ktox=0.395 (0.306-0.453) µg/ml. Comparative analysis showed that cows with the minimum Ktox value (group I) outperformed individuals from I and group II in terms of milk fat yield by 15.4 (P£0.001) and 19.7% (P£0.001), protein by 5.6 and 12.5% (P£0.05), lactose -10.9 (P£0.01) and 18.4% (P£0.001), dry matter by -7.6 and 12.8% (P£0.05) and average daily milk yield by 9.4 and 17.5% (P£0.01), respectively. Thus, in the course of the study, it was registered that with an increase in the total accumulation of heavy metals in the body of animals, the milk productivity of cows decreases.

Feasibility study of flopper stoppers as a passive roll compensation system for offshore construction vessels

Heavy lift vessels are used to install offshore infrastructure. For floating vessels, roll responses can significantly limit their operability, especially for offshore sites where multimodal wave spectra are expected. This paper deals with a numerical study of a heavy lift vessel equipped with submerged flopper stopper (FS) templates suspended from the sides of the vessel. Dynamic analyses for various sizes and numbers of FS templates were conducted. A medium-size (28 m × 14 m) template can increase operational limits by shifting the roll’s natural frequency towards lower values and dampening the responses through drag forces. The operability can increase by about 500% when compared with a vessel without FS templates. A preliminary structural design of a critical beam shows an ultimate limit state design safety factor of 1.5 and fatigue damage of 0.32 for 20 years of service. The cost of construction per template is about $1.75 million (U.S. dollars); the total cost of 4 templates could be recovered in a single wind farm installation project. The system is shown to be feasible for construction vessels used in the execution of marine operations, especially heavy lifting.

Patriarchy and paternalism on a Hungarian collective farm

ABSTRACT The article considers the situation of women in a single Hungarian collective farm - the Red Flag collective farm - in the mid-1970s on the basis of materials collected and interviews made at the time. It considers their work situation, their role in management, their contribution to the cooperative's leadership, and the impact of Hungary's new woman policy of the 1970s. Providing employment for women was a central goal of the farm leadership, but women were concentrated in less skilled jobs and 'female' professions. A few made it to middle management positions, but none got to the top, although they were better represented in party positions. Their contribution to household farming was was determining yet difficult to quantify.