Journal of Arid Environments
Volume 67, Issue 2 , October 2006, Pages 353-356
Response to the comment on “The moisture from the air as water resource in arid region: Hopes, doubt and facts” by Beysens et al.
B. Kogana and A.N. Trahtman HYPERLINK " \l "aff2"b
,mailto:
aECOST, Israel
bDepartment of Mathematics, Bar-Ilan University, 52900, Israel
Article Outline
1. Preface
2. Discussion
3. Conclusion
References
1. Preface
“Comment on “The Moisture from the Air as Water Resource in Arid Region: Hopes, Doubt and Facts” by Kogan and Trahtman (2003)” (hereafter referred to as “Comment” and K&T, respectively) is written mainly by authors of the paper of Nikolayev et al. (1996). One of the conclusions of this paper has been described in our publication as “a rather hasty conclusion”. Therefore, we welcome the appearance of the “Comment” concerning our conclusion. Unfortunately, many aspects of this work are disappointing.
2. Discussion
“Comment” starts with the following surprising sentence: “K&T propose a pyramid-like structure that, they believe, can work as a passive dew condenser. Their theory is based on a dew condenser built by a Russian forester, F.I. Zibold”. However, as early as the next sentence presents another author of the theory: “Zibold had noticed numerous ancient stone heaps in the region and hypothesized that the heaps had once functioned as dew condensers”. Let us add only that Zibold had noticed also a network of tile pipes and channels between stone heaps and water reservoirs. So, it is a theory of Zibold and the theory was not “based on dew condenser of Zibold”, his installation was built essentially later.
“Comment” claims: “The K&T source of information is no more than a two-page report concerning a communication of Zibold”. It is untrue, the vast fragments of Zibold's texts cited in K&T were reproduced in some papers of Alexeyev and Berezkin (1998), Alexeyev and Rustamov (1998), Jumikis (1965), and we used the data and figures from there. The statement about “two-page report” seems especially strange because “Comment” also citied these sources. Nevertheless, “Comment” does not accept Zibold's data and one can find it mostly with a preamble ‘K & T claim…” or ‘K & T write…”.
It is also untrue that we disagree with a dew condensation model that was developed by authors of “Comment” in Nikolayev et al. (1996). On the contrary, this model is estimated in our paper as a model of some kind of condensation. Moreover, we have attract attention to experimental data of night condensation (Nilsson, 1996) that confirms the theoretical model of Nikolayev et al. (1996). The new common investigations by Nilsson and authors of “Comment” (Muselli et al., 2002) only support our opinion. However, this model does not explain the processes in Zibold condenser and it is a real point at issue.
One can compare the statement of the authors of “Comment”: “There are numerous springs in the neighborhood of Feodosia” with their former opinion: “Zibold… was unable to find any natural water sources in Feodosian forest” (Nikolayev et al., 1996). According to “Comment,” only “K&T claim that… there was no trace of springs”. Quite the reverse, this information of Zibold was repeated by many authors, including the authors of “Comment”. Moreover, the whole story of Zibold's condenser is based on the lack of springs near Feodosia. Let us notice that the length of the water pipe to Feodosia according to the Brokhauz–Efron encyclopedia was 18 km. “Comment” lists many details concerning this water pipe, except its length, but just this detail clarifies the situation and refutes the main idea of the passage of “Comment” devoted to natural water sources near Feodosia.
The purpose of the network of ducts and the origin of the layer of mineral deposits in ducts is another point at issue. Nikolayev et al. (1996) and “Comment” believe that it is not the dew water network because dew water cannot produce a layer of mineral deposits. We continue to cite “Comment”: “K&T state that ‘real condensed water contains minerals,’ but make this assertion by mistakenly referring to the quality of fog water, making reference to Schemenauer and Cereceda (1992).” On the contrary, dew water, which is essentially distilled-like water, contains a very small amount of minerals (Muselli et al., 2002)”.
Let us correct our mistake and refer to Muselli et al. (2002) written mostly by the authors of “Comment”. Unexpectedly, we read: “Except for a weak acidity and high concentrations of suspended solids, dew water fits the requirements for potable water…”
Thus the “distilled-like” water has a “high concentrations of suspended solids”! The same is true in the fog case in spite of the “Comment” opinion. The properties of this “distilled-like” (“almost distilled” in Nikolayev et al., 1996) water are the base of the statement in the last paper that “the thick layer of mineral deposits” in tubes “does not come out of condenser.” Does this mean that the “high concentration of suspended solids” could not produce “the layer of mineral deposits”?
Let us go now to the tumuli. The “Comment” states: “Based on the results of the archeological excavations…, the mounds, without exception, proved to be the tombs of either the ancient Greeks or Scythians”. In K&T this opinion was considered: “As for tombs found in stone heaps, we find no contradiction in this situation. Crimea had a large population for many centuries. It is difficult to imagine any place in Crimea without ancient tombs.” We can only add that the redesign of an old tumulus into Zibold's-type condenser seems very natural because the transportation stones from far away is unnecessary.
The shapes of the tumulus and of Zibold's installation are essentially different. The crater of an irregular shape at the top of Zibold's installation is most visible. The purpose of the funnel worries the author of “Comment”, but the explanation seems nevertheless unconvincing: “According to archaeologists (E. Katiushin and J.-P. Morel, personal communications), these Scythian and Greek tombs were designed to be protected by rocks to hinder plundering and that such attempts resulted in these funnels”.
The aim of the passage concerning the funnels is to exclude from the study the possibility of ventilation of stone hills by the help of the funnels. The continuation of the passage makes this intention clear: “The reader is referred to K&T for their mathematical explanation of how ‘air draught’ ventilation within a stone heap can produce condensation during the day. In brief, their models and explanations do not conform to any physical background that we are aware of” Here is the proof: “the dew point temperature… does not change appreciably when the weather is stable.” No explanations why the weather during day and night does not change and is stable. Nevertheless, it is a main part of argumentation, because the conclusion (in italics) follows: “Thus wind, which ultimately imposes air temperature to the condenser, cannot cool the condenser to ensure its functioning”.
Unfortunately, it is far from disproof of our conjecture concerning air draught, the role of the crater and day condensation, even with help of “distilled-like” water. The reasoning of the “Comment” concerning the night condensation is simply off-topic because we consider the day condensation. The phrase “their parameters are confusing or undefined” of “Comment” is devoted to an error in grammar (“grade” instead of “degree”).
Let us note that the designers of real installations (Nilsson, 1996; Schemenauer et al., 1992; Muselli et al., 2002) mentioned the role of weak constant wind for the process of condensation. Therefore the role of air draught in the creation of the weak wind in the Zibold installation and its prototypes needs consideration. Unfortunately, the authors of “Comment” do not see thereupon “any physical background.”
Thousands of small stone heaps in Negev desert “were constructed by ancient settlers in order to increase the amount of flood runoff water” (Evenari et al., 1982). It is interesting to compare the structure of small stone heaps in Crimea (Jumikis, 1965), and in Negev (Evenari et al., 1982) (right).
3. Conclusion
The water supply system of Feodosia was studied by the engineer Zibold because of a constant deterioration at the end of the XIX century. Zibold considered the stone hills of a specific shape as a source of water for this system. If we believe that Zibold's publications reproduced by Alexeyev are not malicious falsehood, then the data and figures of Zibold need explanation. One of the explanations was presented in our paper.
“Comment” is devoted mainly to the refutation of Zibold's conjecture about the role of stone hills as dew condensers. It is difficult to find its arguments satisfactory.
Thus the problem of prototypes of the Zibold installation, of the role of funnels and of the air draught is still open and “the opinion that there were no dew-catching constructions in Crimea is a rather hasty conclusion” (K&T).
References
Alexeyev and Berezkin, 1998 V.V. Alexeyev and M.Ju. Berezkin, Fresh water from air, Priroda6 (1998), pp. 90–96.
Alexeyev and Rustamov, 1998 V.V. Alexeyev and N.A. Rustamov, Water from air, Ecologiya i zhizn1 (1998), pp. 44–47.
Evenari et al., 1982 M. Evenari, L. Shanan and N. Tadmor, Negev, Harvard University Press, Cambridge, MA (1982).
Jumikis, 1965 A.R. Jumikis, Aerial wells: secondary sources of water, Soil Science100 (1965), pp. 83–95.
Kogan and Trahtman, 2003 B. Kogan and A. Trahtman, The moisture from the air as water resource in arid region: hopes, doubt and facts, Journal of Arid Environments53 (2003), pp. 231–240Muselli et al., 2002 M. Muselli, D. Beysens, Ja. Marcillat, I. Milmouk, T. Nilsson and A. Louche, Dew water collector for potable water in Ajaccio, Atmospheric Research64 (2002), pp. 19–35.
Nikolayev et al., 1996 V.S. Nikolayev, D. Beysens, A. Gioda, I. Milmouk, E. Katiushin and J.P. Morel, Water recovery from dew, Journal of Hydrology182 (1996), pp. 19–35.
Nilsson, 1996 T. Nilsson, Initial experiments on dew collection in Sweden and Tanzania, Solar Energy Materials and Solar Cells40 (1996), pp. 23–32.
Schemenauer and Cereceda, 1992 R.S. Schemenauer and P. Cereceda, The quality of fog water collected for domestic and agricultural use in Chile, Journal of Applied Meteorology31 (1992), pp. 275–290.