Tank Farm Research Articles

Comprehensive study on incineration-based disposal of hazardous gas and liquid wastes from used lubricating oil refineries

In this study, an incinerator is researched for the disposal of gaseous and liquid hazardous wastes (HWs) from the used lubricating oil refinery by incineration, following the zero-waste principle. Subsequently, combustion characterization of mixed-content HWs from different entrances of the combustion chamber in the incinerator, simultaneously with natural gas without mixing, is investigated experimentally, theoretically, and numerically. The HWs consist of gaseous ones from distillation and hydroprocessing and from the tank farm, and liquid ones resulting from petroleum refining processes. The results show that the combustion gases from HWs and natural gas are maintained at a minimum of 850 °C for at least 2 s in the 1.6 m diameter and 6 m length incinerator. The upper wall exhibits higher temperatures compared to the lower wall due to the heat generated during combustion, emphasizing the significance of material selection and design to withstand thermal stresses. A comprehensive analysis provides insights into the compatibility of the combustion chamber design with chemical processes, further underlining its contributions to environmental sustainability. Thus, this study demonstrates the effectiveness of mathematical and numerical analyses in improving the incineration process, ensuring the thorough combustion of hazardous waste, and minimizing the formation of harmful by-products.

Numerical investigation on oil leakage and migration from the accidental hole of tank wall in oil terminal of pipeline transportation system

As a crucial component of the oil transportation system, the oil terminal (or oil tank farm) may often pose some serious threats and damage to the ecological environment and production safety for the oil leakage. An effective emergency management strategy is particularly significant, involving the accurate assessment of leakage time, oil migration path, volume distribution, etc. Therefore, the volume of fluid (VOF) and liquid phase leakage model were applied to investigate the migration and distribution characteristic after the accidental hole occurs in the tank wall, and influence factors including height and diameter of the hole were considered in our study. Results show that the lower the leaking hole position is, the faster the horizontal injection rate of the leakage hole, the increase of the accumulation area of the oil on the ground, and the difference in the overall pressure value at the leakage hole is nearly four times. Under different leakage diameters, the oil spill is symmetrical. The larger the leakage diameter, the higher the amount of oil leakage and the initial leakage speed, the maximum speed is 1.5 times the minimum speed, causing harm to safety and environmental pollution. These results can quickly locate the leakage location of the tank and provide valuable references for emergency management of the oil pipeline transportation system.

Socio-Environmental Impacts Assessment of Tank Farm Location and Operation in Port Harcourt Municipality, Rivers State

Socio-Environmental Impacts Assessment of Tank Farm Location and Operation in Port Harcourt Municipality, Rivers State

La calidad higiénica de la leche cruda destinada al consumo humano en Argelia: Metaanálisis

The main goal of this article was to conduct a meta–analysis, to estimate the hygienic quality of the raw milk intended for human consumption and subsequently relative risk factors that may impact milk quality in Algeria. Weighted random–effects meta–analysis models were employed to analyze the data in this study. A total of 4,685 sampling results from 61 included studies, investigating the bacterial quality of raw milk across 35/48 Provinces in Algeria, from 2009 to 2022. In this meta–analysis, the average level of contamination by Total Aerobic Mesophilic Bacteria (TAMB) was 5.84 log10 CFU·mL-1. 95% CI [5.55–6.13]. The P–value was 0.001. The I2 test indicates the presence of substantial statistical heterogeneity across studies; (I2=86.26%, P<0,001). No significant publication bias was observed using the funnel plots and Egger’s test (P=0.885). In this article TAMB values did not differ significantly among species (P>0.05).The average contamination level TAMB was lower in milk samples collected from individual milking and farm tank milk (4.57 log10 CFU·mL-1 and 5.89 log10 CFU·mL-1), compared to those recorded in milk samples collected from the collector, dairy, and sales (6.59 log10 CFU·mL-1, 6.60 log10 CFU·mL-1, and 6.74 log10 CFU·mL-1, respectively). The contamination level of milk by TAMB was higher during summer and spring (6.80 log10 CFU·mL-1 and 6.70 log10 CFU·mL-1), compared to winter and autumn (4.27 log10 CFU·mL-1 and 5.64 log10 CFU·mL-1).

Предремонтная подготовка резервуаров, осложненная пирофорными отложениями

Purpose. One of the most important measures to reduce fire and explosion safety of hot and repair work at oil and oil products storage tanks is premaintenance works. Most oil tank fires occur during this stage. Premaintenance works are significantly complicated by corrosion deposits on tank inner surface. When conducting premaintenance works, there is a risk of spontaneous combustion of pyrophoric sediments. The most frequent cases of catching fires occur at high-sulfur oil tanks with pyrophoric sediments, and that requires a new approach to conducting this technological operation. Methods. Methods of comparison, description and generalization were used in the study. The information basis for the study was scientific sources, regulatory documents and reports of fire analyses at tank farms. Findings. Analysis of practice of operating tanks for storing high-sulfur oil, as well as data on tank fires shows that current approach to premaintenance works is ineffective. It is necessary to adjust current regulatory documentation in the field of improving fire and explosion safety at petrochemical industry facilities and develop new, more effective means of anti-corrosion protection for tanks with high-sulfur oil. Research application field. Analysis and development of regulatory- technical base will allow finding a new approach to methods of premaintenance works and hot works to improve fire and explosion safety at tank farms for storing high-sulfur oil. Conclusions. In-depth studying the problem of storing high-sulfur oil in tanks and the issue of its purification will allow us to find more modern and high-quality methods for conducting premaintenance works to ensure fire and explosion safety at tank farms.

Влияние ограждений вертикальных стальных резервуаров с бензином на снижение потенциального пожарного риска

Purpose. The article discusses the procedure and features of developing logical event trees, which are an integral part of the fire hazard analysis in the assessment of fire risks at industrial facilities and are widely applied at various facilities to be protected, using the example of emergency situations at typical vertical steel tanks (VST) with gasoline. The authors demonstrate the effect of the standard earthen embankment and the enclosing wall with a wave deflector for a VST on reducing the potential fire risk. Methods. The methodological and regulatory basis for developing logical event trees and assessing fire risk are the requirements of the Federal Law of the Russian Federation No. 123-FZ dated 22.07.2008 “Technical Regulations on Fire Safety Requirements”, as well as the “Methodology for Determining Estimated Values of Fire Risk at Industrial Facilities”, approved by Order of EMERCOM of Russia No. 404 dated 10.07.2009. Findings. The paper presents complete logical event trees that can be implemented on RVSs with gasoline, and provides information on the justification of the frequency rate of a fire hazard, even if its standard values are absent. The efficiency of using an enclosing wall with a wave deflector in tank farms is substantiated. For the considered RVS-20000 with gasoline, the use of such a barrier can reduce the potential fire risk in the range from 10–6 to 10–8 year–1 at the corresponding distances from the tank from 7.7 to 13 times, compared with the application of a standard earthen embankment. Research application field. The developed logical event trees and proposals for constructing enclosing walls with a wave deflector in tank farms can be used in activities of EMERCOM of Russia, expert organizations, research and design institutes, as well as higher education institutions and other educational organizations, when resolving issues of confirming the compliance of industrial facilities to be protected with the required level of fire safety based on fire risk assessment within the framework of performing final qualification papers and developing special technical conditions. Conclusions. The use of the obtained results in the educational process will improve the quality of training students who are competent in the following areas: methods of assessing the compliance of the facility to be protected with the requirements of regulations and normative documents; methods for determining the calculated values of fire risk; systems for ensuring fire safety of facilities to be protected aimed at reducing fire risk.

Evaluating the Impact of Barging Activity on Road Decongestion in Apapa Lagos Nigeria: A Case Study of AP Moller Terminal Ltd

The impact of barge transport in the evacuation of port cargoes from the Lagos Port Complex at Apapa in Lagos Nigeria is examined. Traffic gridlock extending from port congestion had made life difficult for inhabitants and users of the port city since the mid-1990s, especially when petrol tanker trucks began to rely on direct loading of refined petroleum products from the port and the petrol tank farms located all over the city. Despite the predominance of waterways, inland waterway transportation had not been well developed leading to intense traffic and commuter problems. Primary and secondary sources of data were used with quantitative and qualitative analytical methodology and analysis of variance (ANOVA) modelling. The findings include the substantial difference made by barges in the transfer of containers to various parts of the Lagos which demonstrably removed many lorries and trucks from the overstretched roads. The conclusion analyzed the impact of a systematic introduction of full barging services in the sea trade of the country and port city dwellers especially.

Рационализация технологической обвязки резервуарного парка при нерегулярной смене сорта нефти

Due to the growing demand for the construction of tank farms and the need to reduce the cost of equipment used irregularly (quarterly) when changing the nomenclature of grades of oil or petroleum products, it is advisable to improve the maintainability and cost-effectiveness of standard technological strapping projects. The paper describes the replacement of standard shut-off valves with a rotary plug (obturator). The economic justification for the choice of rotary plugs in a typical RVS design is given. The analysis of normative and technical documentation and methods of calculation of obturators is carried out. It is established that the introduction of rotary plugs provides an increase in the reliability of standard projects.

Влияние скорости воздушного потока на тепловое излучение от углеводородного пожара в резервуаре для хранения нефти

Purpose. The article assesses the effect of air flow velocity on the intensity of thermal radiation from a fire in a vertical steel tank with a floating roof of 65 000 m3 capacity (VSTWFR-65000) with crude oil. The indicators of hazardous fire factors - open flame, smoke and temperature at different wind speeds – have been studied. Methods. The method of numerical modeling in the Fire Dynamics Simulator software package, as well as the method of processing the obtained research results have been used in the study. Findings. The dependence of the flame inclination angle at different air flow speeds has been obtained. The simulation results have been shown: smoke distribution at different wind speeds, as well as temperature change at a distance from the fire source depending on the air flow velocity. Research application field. The results of the study can be used in the development of design documentation for measures to ensure fire safety of a tank farm with floating roof tanks, as well as in adjusting fire extinguishing plans. Conclusions. Based on the simulation results it has been found that with an increase in the air flow velocity the intensity of thermal radiation initially increases and then decreases. It has been found that at an air flow velocity of 9 m/s the maximum thermal radiation reaches 23.43 kW/m2 at the nearest point of the adjacent tank in the projection from the central axis of the burning tank. At an air flow velocity of 6.5 m/s the temperature at the top of the adjacent tank reaches 176 °C, and at 9 m/s – 426 °C, which is higher than the autoignition temperature of oil, which is within 222–256 °C, there by creating a threat of fire spread. The study has defined the maximum distances from the burning VSTWFR-65000 for the safe presence of people, amounting to 47.3; 48.9; 50.2; 53.4; 55.7; 56.8; 59.4 m for wind speed of classes 0, 1, 2, 3, 4, 5 and 6 respectively.

Экспериментальное определение давления насыщенного пара жидких моторных топлив

Purpose. Currently, new brands of liquid motor fuel are produced, whose fire hazardous properties are not reflected in regulatory documents and reference literature. The values of saturated vapour pressure of petroleum products presented in them differ significantly from each other and that may affect the results of assessing fire and explosion hazard of the facility under protection. The article provides the results of experimental evaluation of motor gasolines and diesel fuel saturated vapour pressure. Methods. Analytical and experimental methods for determining saturated vapour pressure of motor gasolines and diesel fuel have been used during the research process. Findings. The saturated vapour pressures of motor gasoline and diesel fuel of different brands have been determined experimentally. It has been found that saturated vapour pressure of petroleum products is different and varies over a wide range. Research application field. Experimental studies allowed obtaining the numerical value of saturated vapour pressure of currently marketed brands of liquid motor fuel. Conclusions. During the experiments, the values of the saturated vapour pressure of liquid motor fuels, significantly different from those given in the regulatory documents or determined by calculation have been obtained. The application of the obtained results will make it possible to assess fire and explosion hazard of storing flammable liquids in tank farms of the facilities under protection.

Нормативно-технические документы, регламентирующие предремонтную подготовку нефтяных резервуаров

Purpose. One of the most important stages in working out measures for reducing fire and explosion safety of fire and maintenance works on tanks is a qualitative analysis of regulatory documentation containing fire safety requirements for cleansing tanks. Generalization of fire statistics indicates that half of fires connected with pre-maintenance make-ready occur on tanks after they have been cleaned during hot works. This conclusion determines the need for analyzing technical guidance documents and experience in pre-maintenance make-ready in practice. Methods. The article analyzes technical guidance documents in the field of fire and explosion safety of pre-maintenance make-ready and hot works, presents statistical data, and also summarizes practical experience. Findings. The results of the analysis of technical guidance documents regulating the pre-maintenance make-ready of oil tanks led to the conclusion that it is necessary to develop new regulatory documents containing the correct sequence of pre-maintenance make-ready work of oil tanks for ensuring their fire and explosion safety. Research application field. The analysis and elaboration of the regulatory and technical framework will allow finding a new approach to the methods of pre-maintenance make-ready and hot works for improving fire and explosion safety of oil tank farms. Conclusions. Generalization and analysis of scientific and technical documentation indicates that fire and technical requirements are contradictory and do not fully reflect the necessary issues of ensuring fire and explosion safety. The generalization of practical experience shows that the empirical approach does not allow achieving the required level of fire and explosion safety established by GOST 12.1.004-91. To increase the level of fire and explosion safety, a comprehensive study of fire hazard of pre-maintenance make-ready, an experimental and theoretical justification of the quantitative criteria for tanks readiness for hot works, an analysis of fire and technical requirements for the most common in practice technological operations (ventilation, steaming, hydraulic cleansing) and development of fire and explosion safety requirements for hot works on tanks without their preliminary cleansing are necessary.

Методика и алгоритм расчета местных потерь напора в трубопроводах

The article is devoted to the hydraulic calculation of pipelines. For the storage of liquid products used in the national economy, there are tanks, which are usually combined into tank farms. Equipment for transporting liquids within the tank farm includes pumping units, pipelines, shut-off and control devices, etc. The growing needs of the economy create the necessity of build new and expand existing storage facilities for liquid products at industrial and transport objects. Hydraulic calculation is an important part of the tank farms pipeline systems design. This paper presents a methodology and algorithm for determining of local fluid pressure losses in pipelines. The calculation is based on the characteristics of pipeline system sections in which local hydraulic resistance occurs: a change in the diameter or direction of the pipeline, installation locations of auxiliary devices, etc. The Weisbach formula is used to calculate the local pressure losses. This takes into account the values of the local resistances coefficients and average flow velocities in the respective sections. The average flow velocities are determined by the given values of the flow rates and flow profiles on the sections. The local losses coefficients, depending on the type of resistance, are also found according to the calculation formulas, or are set as the initial values. Local pressure losses are calculated for curved sections of pipelines, conical transitions (confusers and diffusers), inlet and outlet sections, shut-off, control and safety valves, instrumentation, branches.

Dynamic Domino Effect Assessment (D2EA) in tank farms using a machine learning-based approach

The current work presents a Dynamic Domino Effect Assessment (D2EA) methodology for chemical storage tank farms. While the application of the proposed approach is focused on atmospheric tanks, it applies as well to pressurized tanks. It utilizes the temperature and time-dependent material strength property (yield strength) as a structural health indicator. The D2EA methodology uses random forest (RF) and feed-forward neural network (FFNN) to predict yield strength during fire exposure and applies the predicted yield strength to dynamic failure assessment. A lumped parameter model generates datasets to train the dynamic failure prediction model. Two case studies have been used to demonstrate how the method can be used. The results suggest that RF and FFNN can predict gamma distribution-aided dynamic failure probability assessment. The RF is a better tool than FFNN due to its lower computational cost and good performance. The current work will be helpful in the design and operation of tank farms – an essential and critical infrastructure.

Ecological dynamic of fish farming ponds managed during the growth of matrinxã (Brycon amazonicus)

Habitat for organisms in ecosystems include attributes to the ecological significance and resulting from the interactions between its physical, chemical and biological components. In fishponds, one of the important features is the community of the microzooplankton that é key component of marine food webs and food chain in freshwater. An experiment was carried out in an area for fish farming, located in Assis Brasil Village, municipality of Cruzeiro do Sul, State of Acre, aimed to observe the dynamics of fish farming tanks, and the composition and microzooplankton abundance, submitted to two treatments, commercial feed (ad libitum) and tabulated feed. The results showed that environments severely eutrophicated are characterized by high values of phosphorus and nitrogen, and dominance of species of Rotifera, throughout the study. On this basis, it was concluded that researches of this nature contributes for determining the water quality, particularly using potential bioindicator species, that grow excessively in these environments.

ОЦЕНКА ВЕРОЯТНОСТИ РЕАЛИЗАЦИИ НА ГОЛОВНОЙ НЕФТЕПЕРЕКАЧИВАЮЩЕЙ СТАНЦИИ АВАРИЙНЫХ СИТУАЦИЙ, ПРОТЕКАЮЩИХ ПО РАЗЛИЧНЫМ СЦЕНАРИЯМ

The work of enterprises in the agro-industrial complex is closely connected with the use of petroleum products, the use of which is ensured through oil pumping stations. The assessment of the probability of emergency situations at such enterprises was carried out using the example of the main oil pumping station GNPS-1 “Taishet” of TransnefteVostok LLC. It is shown that the enterprise belongs to objects of increased fire danger, the most dangerous technological areas of which are the tank farm, the main oil pumping station and the booster pumping station. A fire and explosive substance - oil is circulated in a technological scheme. Possible ways of developing emergency situations associated with the failure of equipment in individual technological sections of an oil pumping station were investigated in the work. The most dangerous accidents occur in three areas: in the tank farm, at the main and booster pumping stations. The probabilities for the development of emergency situations have been determined. It was revealed that the most dangerous scenarios are possible at any of the reservoirs of the tank farm and at the main oil pumping and booster pumping station. In both scenarios, an instant spill fire, a spill fire with delayed ignition, and an explosion of a vapor-air cloud are possible. The cause may be a failure of emergency ventilation and a vapor-air cloud gas analyzer. The studied options for the development of an accident on technological equipment will make it possible to establish the scale of the consequences of the spread of dangerous factors of fire and explosion, as well as to determine a set of measures to prevent emergency situations, timely response and minimize their consequences.

Improved pool fire-initiated domino effect assessment in atmospheric tank farms using structural response

Domino effects are severe accident scenarios affecting storage tanks and are often initiated by pool fires. Flame engulfment and heat radiation are the two major sources triggering domino effect. Threshold-based and probit-based methods are widely used to assess the possibility and probability of a secondary accident. These methods are also a part of advanced methods devoted to examining synergic or coupling effects. The current work examines (i) how effective the threshold-based methods are and (ii) how accurate the current time to failure (TTF) estimation models are, which are the basis of probit-based methods. The results suggest that threshold-based methods are not pertinent for the quantitative assessment of domino effect and that significant improvement can be made in the existing TTF prediction models using site-specific structural response data. A new set of equations for TTF estimation using data analytics is proposed. Application to 4,080 pool fire scenarios demonstrates that the newly developed model can improve the TTF prediction performance compared to the existing models (around 22% in terms of R2). In addition, a method has been proposed and validated to correlate time with the failure probability for time-dependent domino effect assessment, which is a limitation of probit-based methods.

Hermetia illucens Fermented with Lactobacillus plantarum KCCM12757P Alleviates Dextran Sodium Sulfate-Induced Colitis in Mice.

Inflammatory bowel disease (IBD) can severely affect humans and animals and is difficult to treat. Black soldier fly (Hermetia illucens; Hi) larvae (BSFL) are a sustainable source of protein. However, no studies exist on the antioxidant and anti-inflammatory functions of BSFL or fermented BSFL with respect to IBD. In this study, riboflavin-producing Lactobacillus plantarum KCCM12757P was isolated from a fish farm tank, and in conjunction with hot water-extracted Hi (HeHi) (termed HeHi_Lp), was used to determine optimal fermentation conditions to increase vitamin B2 concentration. This in vivo study investigated the therapeutic effects and mechanistic role of HeHi_Lp in chronic colitis-induced murine models. Histological changes, inflammatory cytokine levels, and intestinal barrier function were explored. Gut microbial communities and gene expression in the nuclear factor (NF)-κB signaling pathway were also studied. HeHi_Lp remarkably reduced the disease activity index, inflammatory cytokine (inducible nitric oxide synthase, cyclooxygenase 2, tumor necrosis factor α, interleukin (IL-6 and IL-1β) levels, and increased body weight and colon length. HeHi_Lp administration significantly raised zonula occludens 1, occludin and claudin 1 and improved the composition of the gut microbiota and beneficial intestinal bacteria. These results suggest that HeHi_Lp can be used as a dietary supplement in pet food to alleviate colitis.

INVESTIGATION OF THE EFFECT OF CLAPS ON THE STRESS-STRAIN STATE OF TANK STRUCTURES

The need to study the problems of reliable operation of the reservoir system is relevant. Special attention should be paid to the specifics of the operation of oil storage tanks and their equipment. The Russian tank farm was formed in the 1970s, a significant part of it has a service life of more than 50 years. The experience of examining such structures with a long service life indicates the presence, in most cases, of the physical aging of their structural elements.
 The article presents the results of processing a cloud of points created using a ground laser scanner to determine the actual geometric deviations of the reservoir and their combined effect on the reliability of the reservoir.
 During the survey, a method of work was used that differs from the standard. In the field, a laser scanner was used instead of a theodolite; in office processing, software systems were used that simplify the tasks.
 In the process of research in the 3DR software package, a triangulation mesh model was created from a cloud of points from a set of finite elements to identify defects located on the wall. The data obtained can be compared with previous and future survey results. Also, the model can be used to create a calculation scheme in PC LIRA 10.
 We set the actual characteristics of the tank wall to the finite elements (the thickness of the first belt is 12 mm, the next ones 10 mm). The main load combinations were applied to the tank. The calculations were carried out for a combination of loads, including the own weight of the structures, the pressure of the stored product and the overpressure in the gas space. Circular and equivalent stresses according to the 4 (energy) theory of strength were analyzed.
 The use of a laser scanner and software systems reduces labor costs for tank inspection, improves the quality of work performed, makes it possible to see the real surface of the tank and take into account defects in the aggregate.
 This method is of practical importance and is currently used by the Department of Inspection of Buildings and Structures.

Bionomics and population dynamics of anopheline larvae from an area dominated by fish farming tanks in northern Brazilian Amazon.

In Brazilian Amazon, deforestation and other anthropogenic activities as a consequence of human occupation have created new and artificial larval habitats for anopheline mosquitoes, providing conditions for oviposition, development and expansion of malaria vector populations. This study aimed to structurally characterize and describe the entomological and limnological parameters of Anopheles larval habitats from a malaria region in northern Brazilian Amazon. Fifty-two larval habitats were investigated in the District of Ilha de Santana, in the Brazilian state of Amapá, comprising fish farming tanks, ponds, and streams. For entomological parameters, the immature larvae were collected monthly from July 2019 to June 2020. For limnological parameters, the water samples were collected from 20 larval habitats during the sampling period. The data were analyzed using Generalized Linear Models, Multivariate analyses, and Kruskal-Wallis tests. Fifty habitats were positive for Anopheles larvae and a total of nine species were collected. The fish farming tanks had the highest abundance of larvae compared with ponds and streams. Anopheles darlingi, Anopheles nuneztovari s.l. and Anopheles triannulatus were collected in 94% of the larval habitats and showed the highest positivity index. The degree of shade and the type of water of the breeding sites were important factors for the presence of the main malaria vector, A. darlingi. This species was the most affected by pH, total dissolved solids, electrical conductivity, and nitrate. Our findings indicate that fish farming tanks are major contributors to vector anopheline abundance and malaria transmission. Vector control strategies focused on these habitats are urgently needed.

Farm management and economic factors associated with bulk tank total bacterial count in Holstein dairy herds in Iran.

The objectives of this research were (1) to study different factors affecting milk total bacterial count (TBC) and (2) to estimate the economic value associated with TBC in Holstein dairy herds in Iran. The relationships between bulk tank TBC and farm management and economic factors were examined on 56 randomly selected intensive dairy farms. Herd management factors associated with bulk tank TBC were determined using mixed linear models. The median bulk tank TBC for the sample herds was 299 (range 81-1185) × 103 cfu/ml. The average economic premium opportunity from bulk tank TBC was US$ 1.32 per ton of milk ranging from US$ 0.02 per ton of milk for herds applying wet tissue procedures as teat cleaning material and washing the water troughs three times per day to US$ 5.20 per ton of milk for herds with dirty barns. Results showed that the following management factors were associated with low TBC and high economic value: frequency of cleaning water troughs, teat cleaning material, the frequency of milk delivery to the processor, bedding material, herd size, education level of workers, udder washing material, material of milking parlor wall, frequency of disinfection of the calving area, presence of veterinarian, water quality control, having a hospital pen and barn hygiene. In conclusion, our findings highlight the need to pay more attention to farm management issues, particularly farm hygiene practices to reduce milk TBC and so reduce the economic burden of TBC in dairy herds in Iran.