**About the Special Issue Editors**

**Yuzhuo Cai**, Dr., is a Senior Lecturer and Adjunct Professor of higher education administration at the Faculty of Management and Business, Tampere University, Finland. He has been with Tampere University for 18 years and was the Acting Professor of Higher Education Administration from August 2013 to July 2014. He is serving as a Guest Professor at both the Institute of International and Comparative Education, Beijing Normal University, and the Institute of China's Science, Technology and Education Policy, Zhejiang University in China. He is a doctoral student supervisor at Peking University. He is the co-director of the Sino-Finnish Education Research Centre, jointly coordinated by Tampere University and Beijing Normal University. He is a board member of the Triple Helix Association and an associate editor of the *Triple Helix: A Journal of University-Industry-Government Innovation and Entrepreneurship*. He is the Chair of the 18th Triple Helix Conference, 15–16 June, 2020, Tampere, Finland. His main teaching and research areas are higher education policy and management, organization theory, science and innovation policies, and internationalization of higher education, with over 100 scholarly publications.

**Jinyuan Ma**, Dr., is a Research Associate Professor at the Center for Higher Education Research, Southern University of Science and Technology (CHER/SUSTech). She received her Ph.D. in Higher Education/Comparative and International Education from the Faculty of Education, the University of Hong Kong (HKU), in 2015. She was the Chief of Research Office, International Centre for Higher Education Innovation under the auspices of UNESCO (UNESCO-ICHEI) as a founding member. Before perusing her Ph.D., she worked for the United Nations Economic and Social Commission for Asia and Pacific (UNESCAP) from 2007 to 2010. She also worked for the Education Sector of UNESCO Beijing Office from 2003 to 2005. Her research interests are liberal arts education in science and engineering universities, societal impact assessment of universities' international research collaboration, and the role of universities in transnational and regional innovation systems.

**Qiongqiong Chen**, Dr., received her Ph.D. in Sociology of Education at the State University of New York at Buffalo, USA. She is currently working as a Researcher in the Office of Strategic Planning and Educational Development of Southern University of Science and Technology (SUSTech) and as a Research Fellow at the Centre for Higher Education Research of SUSTech. Her research interests focus on social and policy studies in higher education; globalization, internationalization and educational reforms; academic mobility; and academic professions. Her book, Globalization and Transnational Academic Mobility, was published in 2017 by Higher Education Press and Springer. Her work also appears in several journals and volumes, including the *Journal of Globalisation*, *Societies*, and *Education*, U.S. Education in a World of Migration, 2013 Routledge World Yearbook of Education, and the Handbook of Globalization and Higher Education.


**Type-2 Fuzzy Logic for Edge Detection of Gray Scale Images**

Abdullah Gubbi and Mohammad Fazle Azeem *Department of Electronics and Communication Engineering PA College of Engineering, Mangalore, Karnataka India*


**7. Postharvest bacterial diseases**

Phytopathogenic bacteria cause postharvest diseases of economically important vegetables. Different species of bacteria belonging to top ten genera viz. *Pseudomonas*; *Ralstonia*; *Agrobacterium*; *Xanthomonas*; *Xanthomonas*; *Xanthomonas*; *Erwinia*; *Xylella*; *Dickeya* (*dadantii* and *solani*); *Pectobacterium* are devastating plant pathogens [18, 19]. They are unable to penetrate directly into plant tissue; however, they enter through wounds or natural plant openings. Wounds can be caused by insects and tools during operations like pruning and picking of the produce. The bacteria only become more active and cause infection when factors are conducive. Factors conducive to infection

*Postharvest Diseases of Vegetable Crops and Their Management DOI: http://dx.doi.org/10.5772/intechopen.101852*

are high humidity, crowding, poor air circulation, plant stress caused by overwatering, under watering, or irregular watering, poor soil health, and deficient or excess nutrients. The bacteria multiply quickly when free moisture and moderate temperatures are available. The major causal agents of bacterial soft rots are various species of *Erwinia*, *Pseudomonas*, *Bacillus*, *Lactobacillus,* and *Xanthomonas. Psuedomonas syringae* pv. *syringae*, *P. syringae* pv. *pisi* and *P. syringae* pv. *phaseolicola* causes diseases in vegetables [20]. The symptoms appear as water-soaked spots on pods that become sunken and dark-brown in color with distinctive reddish-brown margins.

Biological (culture media, diagnostic hosts, bacteriophages (phage typing); biochemical (based on properties of the bacteria in culture (gram stain, bacterial cell size, flagella), metabolic fingerprinting (API/BIOLOG system), thin layer chromatography, gel electrophoresis, conductance assays, isozyme analysis); immunoassays (agglutination, gel diffusion, ELISA, dot blot assays, immunofluorescence, flow cytometry); nucleic acid (hybridization, RFLPs, PCR, ICAN, DNA arrays, multilocus sequence typing) were used for reliable and accurate detection of plant pathogens for their effective management.

### **7.1** *Xanthomonas***: blight**

*X. campestris* pv. *vesicatoria* now reclassified as *X. euvesicatoria*, the causal agent of bacterial spot of tomato. The disease is prevalent in warm, humid, and temperate regions of the world. The genus *Xanthomonas* comprises 20 different species [21] with many pathovars causing economically important diseases on different vegetable crops [22]. *Xanthomonas* is a rod-shaped, gram-negative bacterium. It produces a yellow soluble pigment, called xanthomonadin, and extracellular polysaccharide (EPS). EPS is an important pathogenicity factor of bacteria that protect from desiccation and for the attenuation of wind- and rain-borne dispersal (**Figure 7**).

#### **7.2** *Pseudomonas***: blight**

The disease is caused by pathogen, *Pseudomonas syringae* pv. *pisi*. Another bacterium, *P. syringae* pv. *syringae* has also been reported to infect vegetable pea in a temperate region. Tender pods are chocolate brown, thin, twisted, and

#### **Figure 7.**

Xanthomonas *blight (A and B) and* Pectobacterium *soft rot (C) and culture plate of* Xanthomonas *(D and E) and* Pectobacterium *sp. (A)* Xanthomonas *tomato speck, (B)* Xanthomonas *blight on kale, (C)* Pectobacterium *soft rot on cauliflower, (D)* Xanthomonas *NA culture plate, (E)* Xanthomonas *NA culture plate, (F)* Pectobacterium *NA culture plate.*

#### **Table 4.**

*Postharvest bacterial diseases/pathosystem of vegetable crops.*

shriveled. Lesions are large on older pods and they become thin, twisted, and dry. Seeds become discolored and shriveled. Dried bacterial ooze makes the pod surface glossy.

#### **7.3** *Pectobacterium***: soft rot**

*Pectobacterium carotovorum* and *Pectobacterium atrosepticum* (formerly *Erwinia carotovora* subspecies *carotovora* and subspecies *atroseptica)* causes huge losses of economically important fleshy vegetables worldwide. *P. atrosepticum* was the first genomically sequenced plant bacterial pathogen that is taxonomically related to animal pathogens. Genomic information is now available for *P. carotovorum* strains and other "former Erwinia" species now reclassified in the genus Dickeya. Geographically, *P. carotovorum* is widely distributed and causes soft rot diseases of several vegetable crops. However, *P. atrosepticum* is an economically important pathogen of blackleg disease of potato and restricted into the temperate region of the world (**Table 4**) [23].

#### **8. Postharvest disease management**

Postharvest losses in vegetables are found due to fungal and bacterial infection worldwide. New challenges are faced under trade liberalization and globalization, and serious efforts are needed to reduce these losses in vegetables.

#### **8.1 Chemical control**

Chemical fungicides are commonly used for the management of postharvest disease in vegetables. For postharvest pathogens which infect produce before harvest, the fungicides should be applied at field level during the crop season, and/or strategically applied as systemic fungicides. At the postharvest level, the fungicides are often applied to reduce infections already established in the surface tissues of produce or they may protect against infections occurring during storage and handling. Fungicides used during postharvest are actually fungistatic rather than fungicidal under normal usage. The fungicides are applied on the produce as dips, sprays, fumigants, treated wraps, and box liners or in waxes and coatings. Dip and spray methods are very common in postharvest treatments. The fungicides generally applied as a dip or spray method are benzimidazoles (e.g. benomyl and thiabendazole) against anthracnose, and triazoles (e.g. prochloraz and imazalil) and fumigants, such as sulfur dioxide, for the control of gray mold used for postharvest disease control [24, 25]. Dipping in hot water (at 50°C for 5–10 min, depending on the size of produce in combination with the fungicide) is also used for effective control of the disease. Sodium hypochlorite as a disinfectant is used to kill spores of pathogens present on the surface of the vegetable produce.


**1. Introduction**

It is well known that modern anti-aircraft artillery systems consist of a number of guns, some of which fire at the designated target, while the remaining guns follow the target without firing a shot. This is due to the timing of the single cannon being fired, which is chosen because the high temperatures in the barrel prevent the gun from being fired. In the case of overheating the barrel of one of the guns, it loses its ability to fire. Shooting is then taken over by the other guns that track the target on standby mode. It is also possible to fire all battery guns at once. Low barrel life is a bottleneck that limits the improvement of the weapon's performance for a long time. Many years of research have shown that the erosion of the internal bore is a direct cause that affects the service life of the barrel. The erosion of the inner surface of the barrel is caused by the action of heat, chemistry and mechanics, with heat playing a leading role [1–8]. Although the mechanism of gun barrel wear is not fully understood, it is known that wear is very closely related to the maximum temperature of the bore surface [9]. Usually, when designing the firing cycle, it is essential to maintain the temperature below 800 ◦C, established by the manufacturer as a maximum temperature when testing the gun barrel's life [9,10]. The maximum temperature limit of the barrel bore in operation is dictated by the thermophysical properties of the steel grade of the barrel. In the steel grades under consideration in our paper, a temperature above 800 ◦C causes allotropic changes connected with the reconstruction of the crystal lattice of the alloy [11,12]. The kinetics of change is well described by the dilatometric

**Citation:** Zieli ´nski, M.; Koniorczyk, P.; Surma, Z.; Zmywaczyk, J.; Preiskorn, M. Numerical Study of Heat Transfer in a Gun Barrel Made of Selected Steels. *Energies* **2022**, *15*, 1868. https://doi.org/10.3390/ en15051868

Academic Editor: Dmitry Eskin

Received: 13 January 2022 Accepted: 25 February 2022 Published: 3 March 2022

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curve characteristics for the individual steel grades [11–13]. The effect of temperature on the barrel bore alters the volume of the surface layer, giving rise to a typical mesh of cracks. This affects the flaking off of the protective coating on the inner surface of the barrel. In older technological processes, the protective coating consists of electroplated chromium. Currently, this process is being replaced by nitriding. In any case, the protective coating is corroded by the structural transformations in the steel layer, which are directly related to the phase transition between ferrite and austenite [3,12,14]. At present, research is being conducted on the implementation of new steel grades with a higher allotropic transition temperature into the production of gun barrels [12]. It is about shifting the ferrite–austenite phase transition towards a higher temperature or using steels in which this transition does not take place [11]. When calculating the heat transfer in the barrel, constant values of thermal conductivity, specific heat and the density of the barrel material are often taken [9,14,15]. Many publications believe that the thermal properties of the gun barrel material are temperature dependent [16–20]. As a rule, the temperature dependence of the barrel material density is neglected due to small changes [16]. It is very important to correctly introduce the thermophysical properties of new steel grades as input data for the heat transfer calculations in the barrel. We consider a phase change only in relation to the thermal conductivity. However, in the literature, one can find papers in which the thermal effect of the phase transformation has been included twice, i.e., in thermal conductivity and specific heat, which seems to be an erroneous [16]. Thermal diffusivity *a*, thermal conductivity *k*, specific heat *cp* and density *ρ* are related to the expression *a = k/(ρ*·*cp)*. Each of these thermophysical parameters can be determined on separate measuring stations or, for example, the thermal conductivity can be calculated from the expression *k=a*·*ρ*·*cp*. The phase transformation is visible in each thermophysical parameter. Thus, when calculating the thermal conductivity *k* in the phase transition region from formula *k=a*·*ρ*·*cp*, this effect will be taken into account both in thermal diffusivity and in specific heat. This means that the phase change effect and the associated enthalpy will be accounted for twice. As a rule, we consider the phase transition effect in thermal conductivity characteristic [21]. During the continuous firing of artillery, the inner wall of the barrel will experience a continuous rise of temperature. On each curve of the barrel temperature increase during the shot we can distinguish the so-called highest peak temperature and lowest temperature of the peak base, which is in fact the inner wall temperature of the barrel. In order to reach the temperature of 800 ◦C of the inner barrel surface, it is often necessary to carry out numerical simulations of the heat transfer in the barrel after firing several dozen shots [14,18,19].

Over the years, numerous research groups have carried out a series of tests to determine the temperature field of the gun barrel. These calculations are becoming more and more accurate and verifiable in experimental research [1,15,22,23]. However, it is often important to simulate heat transfer throughout the barrel, not just a fragment of it. In order to avoid very time-consuming calculations, the barrel can be divided into sectors. In this paper an initial boundary value problem (IBVP) of heat transfer in the barrel wall of a 35 mm caliber cannon was solved for the single shot and the sequence of seven shots for chosen barrel steels. For calculation purposes, the barrel with a total length of 3150 mm has been divided into six zones S1 to S6—Figure 1. The heat transfer coefficient was calculated as a function of the time *hi*(*t*) in the six cross-sections P1 to P6 on the inner surface of the barrel: P1: z = 216 mm, P2: z = 385 mm, P3: z = 535 mm, P4: z = 880 mm, P5: z = 2081 mm, P6: z=2980 mm and the gas temperature as a function of time *Tg*(*t*). The functions *hi*(*t*) in cross-sections P1 to P6 are valid in the zones S1 to S6. Additionally, the S0 zone of the cannon breech was distinguished in the range from 0 to 216 mm, for which—at the present stage of the research—the same function *hi*(*t*) was assigned as for the S1 zone. The calculations were carried out considering the temperature-dependent thermophysical parameters in the model, i.e., thermal conductivity, specific heat and thermal expansion (in the range from RT to 1000 ◦C). In 2020, the authors of this study tested the thermophysical properties of selected barrel steels, i.e., 38HMJ (1.8509), 30HN2MFA and DUPLEX (1.4462) (in the range from RT to 1000 ◦C) [12]. In this study, particular attention was paid to the correct

introduction of thermophysical parameters depending on the temperature in the numerical heat transfer tests in the barrel wall of a 35 mm caliber cannon for a single shot and the sequence of shots for the chosen barrel steels. The idea is not to erroneously consider the phase transition effects on the selected metals twice, such as in thermal conductivity and specific heat.

**Figure 1.** Heat transfer zones S1 to S6 of the 35 mm cannon barrel input to the calculations: S1: 0 ÷ 385 mm, *rout* = 55.0 ÷ 55.0 mm; S2: 385 ÷ 535 mm, *rout* = 55.0 ÷ 57.0 mm; S3: 535 ÷ 880 mm, *rout* = 57.0 ÷ 59.5 mm; S4: 880 ÷ 2081 mm, *rout* = 59.5 ÷ 44.07 mm; S5: 2081 ÷ 2980 mm, *rout* = 44.07 ÷ 31.0 mm; S6: 2980 ÷ 3150 mm, *rout* = 31.0 mm. The zone S1 includes the zone S0 of the cannon breech (reproduced with permission from [24], Military University of Technology, 2022).


**9. Conclusions**

PVA hydrogel and ferrogels with Fe3 O4 micro- and nano-sized particles as fillers have been successfully prepared by freezing-thawing (F-T) cyclic method. We can conclude the chapter as the following: