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Privacy Policy — Mohr's Circle

Last updated: September 14, 2026

This policy explains how the Mohr's Circle app (package com.celesiob.mohr), developed by Celésio Batistoni and distributed through Google Play, handles information. By installing or using the app, you agree to the practices described here.

1. Summary

The app does not collect, transmit or sell personal data. Everything you type and calculate stays on your device. The app shows ads from Google AdMob, and for that purpose Google may process data from your device. You control that processing through the consent notice and your Android settings.

2. Data collected by the developer

None. The app has no sign-up, no login, no contact form, no usage analytics, no crash reporting and no server of its own. The developer does not receive and cannot access anything you do in the app.

3. Data stored on your device

To work, the app stores locally:

• Calculation history: the stresses you enter, the results, and the date of each saved calculation.

• Preferences: theme (light, dark or automatic), chart font scale, display options (three circles, wedge), acceptance of the legal notice, and your progress in the practice and quiz modules.

• Temporary files: the PDF reports you generate are kept in the app's cache area until the system discards them.

This data lives in the app's private storage, accessible only to the app. None of it is sent to the developer. You can erase all of it in Android Settings > Apps > Mohr's Circle > Storage > Clear data, or by uninstalling the app.

4. Android backup

Android may include the data described in section 3 in the automatic backup of your Google account, if backup is enabled on your device. That backup is a Google service, governed by Google's Privacy Policy, and the developer has no access to it. To turn it off: Android Settings > Google > Backup.

5. Advertising (Google AdMob)

The app is free and shows ads served by Google AdMob: banners on the screens and rewarded ads, which you watch by your own choice to unlock features.

To serve and measure ads, Google may process:

• your device's Android advertising ID;

• your IP address (from which an approximate location is derived);

• device information such as model, OS version and language;

• ad interactions (impression, tap).

This processing is carried out by Google, acting as controller of that data. See:

• Google Privacy Policy: https://policies.google.com/privacy

• How Google uses information from apps that use its services: https://policies.google.com/technologies/partner-sites

You can reset or delete your advertising ID in Android Settings > Google > All services > Ads.

6. Advertising consent

In the European Economic Area, the United Kingdom, Switzerland, and anywhere else the law requires it, the app displays a Google consent form (User Messaging Platform) before loading any ad. Your choice is stored on the device and honoured on later runs.

You can review or change that choice at any time through the "Privacy options" item in the app menu.

7. Promotion of the developer's other apps

A section of the app may promote other apps by the same developer. That list is bundled inside the app, is not personalised and involves no data collection; tapping it simply opens the corresponding Google Play page.

8. Sharing reports

PDF reports are generated entirely on your device. They leave it only if you tap share and pick a destination. From that point on, the file is handled by the app you chose (email, messenger, cloud storage).

9. Permissions

The app requests only two permissions, both used exclusively to load ads and check connectivity:

• INTERNET (network access);

• ACCESS_NETWORK_STATE (check connection state).

The app does not request access to the camera, microphone, precise location, contacts, calendar, photos or device files.

10. Children

The app is aimed at engineering students and professionals and is not directed to children. The developer does not knowingly collect data from minors. If you are responsible for a minor who uses the app and have any concern, contact the address in section 15.

11. Your rights

Since the developer collects no personal data, there is no personal database under the developer's control to access, correct or delete.

As for the data processed by Google for advertising purposes, you may exercise your rights — access, rectification, erasure, objection, portability and withdrawal of consent — directly with Google, through the channels listed in Google's Privacy Policy, in addition to the controls described in sections 5 and 6.

These rights arise, depending on your country, from the General Data Protection Regulation (GDPR, EU and UK), the California Consumer Privacy Act (CCPA/CPRA), Brazil's General Data Protection Law (LGPD, Law 13.709/2018) and equivalent legislation. The developer does not sell or share personal data for third-party behavioural advertising beyond what is described in section 5.

12. International transfers

Data processed by Google for advertising may be handled on servers located in other countries, under the safeguards described in Google's Privacy Policy.

13. Security

Local data is protected by Android's app sandboxing. As nothing is transmitted to the developer, there is no server-side storage under the developer's responsibility. No storage method is completely secure; keep your device's system up to date.

14. Changes to this policy

This policy may be updated to reflect changes in the app or in applicable law. The date at the top shows the last revision. Material changes will be noted in the update description on Google Play. Continued use after a new version is published means you accept it.

15. Contact

Questions about this policy can be sent to:

Celésio Batistoni
celesiobatistoni@gmail.com

Terms of Use — Mohr's Circle

Last updated: September 14, 2026

These Terms govern the use of the Mohr's Circle app (package com.celesiob.mohr), developed by Celésio Batistoni and distributed through Google Play. By installing, opening or using the app, you confirm that you have read, understood and accept these Terms. If you do not agree with them, do not use the app.

1. What the app is

Mohr's Circle is an educational tool for studying and solving stress and strain states: plane-stress Mohr's circle, triaxial state, failure theories, step-by-step calculation report, PDF export, and a learning module with worked examples, practice and a quiz. It is study and cross-checking material.

2. Engineering disclaimer

This is the most important section of these Terms.

This app is intended for educational, informational and study purposes. Its results must not be used as the sole basis for real engineering projects.

The app does not replace a detailed analysis or the judgement of a qualified professional, who must independently verify any result before using it in design, manufacturing or safety assessment.

Use of the app and of its results is entirely at your own risk. The app is provided "as is" and "as available", without warranties of any kind, express or implied, including accuracy, fitness for a particular purpose or freedom from error.

The sign conventions used (tension positive; τxy positive in the +y direction on the +x face; counter-clockwise angles positive; the chart's τ axis positive downwards) are described inside the app. Different conventions, used by other textbooks, standards or instructors, produce different signs: check the convention before comparing results.

3. Licence

The developer grants you a free, personal, non-transferable, non-exclusive and revocable licence to install and use the app on devices you control, for personal, academic or professional study purposes.

This licence transfers no ownership of the app or of any part of it.

4. Prohibited uses

You agree not to:

• copy, distribute, sublicense, sell or rent the app or its installation file;

• decompile, reverse-engineer or attempt to extract the source code, except to the extent expressly permitted by law;

• modify the app, circumvent limitations or remove the display of ads;

• generate ad taps or impressions in an automated, fraudulent or artificial way;

• use the app for any unlawful purpose or in violation of third-party rights.

5. Ads and rewarded features

The app is free and supported by Google AdMob advertising. Some features may be unlocked temporarily after a rewarded ad, watched by your own choice.

The developer does not guarantee continuous availability of ads or of the features tied to them, as both depend on connectivity and on the ad network. Data handling related to ads is described in the Privacy Policy.

6. Intellectual property

The app, its code, icon, visual identity, educational texts, worked examples, quiz questions and other original content are owned by the developer and protected by copyright law.

The mathematical formulations, formulas and concepts of strength of materials presented here are in the public domain; the way they have been written, organised and illustrated is not.

Third-party trademarks mentioned (Google, Google Play, Android, AdMob) belong to their respective owners.

7. Reports you generate

The PDF reports produced by the app are yours. You may use them freely, including in academic work and internal documents, subject to section 2 and to your institution's rules on citing sources. You are solely responsible for the content and use of those reports.

8. Availability and changes

The developer may, at any time and without prior notice, fix, change, add or remove features, as well as suspend or discontinue the app. Updates may be required for correct operation.

9. Limitation of liability

To the fullest extent permitted by applicable law, the developer shall not be liable for direct, indirect, incidental, special or consequential damages, including financial loss, property damage, data loss or lost profits, arising from the use of or inability to use the app, or from decisions made on the basis of its results.

Nothing in these Terms excludes or limits liability that cannot be excluded or limited under applicable law, including consumer protection legislation.

10. Privacy

Information handling is described in the app's Privacy Policy, which forms part of these Terms.

11. Term and termination

These Terms apply for as long as you use the app. The licence in section 3 terminates automatically if you breach any provision of these Terms; simply uninstall the app.

12. Changes to these terms

These Terms may be updated. The date at the top shows the last revision. Continued use of the app after a new version is published means you accept it.

13. Governing law

These Terms are governed by the laws of the Federative Republic of Brazil. Where mandatory consumer protection rules of your country of residence apply, they are not affected by this clause.

14. Relationship with Google

Google Play acts only as a distribution platform. Google is not a party to these Terms, does not sponsor or endorse the app and is not responsible for it.

15. Contact

Celésio Batistoni
celesiobatistoni@gmail.com